NEW YORK (Fortune) -- Ankur Moitra has hit the internship jackpot.

The 20-year-old engineering student has a top project at Google Finance this summer - developing a search algorithm for the site's blog section. If he succeeds, he can take pride in knowing millions of users will benefit from his work.

Megan Williams, a college sophomore and intern at Northwestern Mutual Financial Network, pitches insurance products to a prospective client.

More from Fortune Will Mmmhops be a hit? NBA confirms L.A. Clippers sale to ex-Microsoft CEO Steve Ballmer FBI and SEC probe into Carl Icahn and golfer Phil Mickelson FORTUNE 500 Current Issue Subscribe to Fortune

His job also comes with many perks, like three free meals a day, freedom to set his own hours and a salary that more than doubles what he made at his Citigroup internship.

Moitra, a Cornell senior who exudes upper-manager confidence, is like many other college students working this summer. He wants substantive work to show for his time.

"The stereotype of an intern being stuck in the mailroom is becoming a thing of the past," says Steven Rothberg, president of CollegeRecruiter.com, a job site targeting students and recent graduates.

Students have more resources than ever for landing meaty internships. Web forums and discussion groups dole out good tidbits about different programs, and sites like MonsterTRAK.com offer thousands of job postings to pick from.

At the same time, companies are increasingly seeing internship programs as crucial for finding future talent.

It is no surprise then that students, especially those at the top, can be choosy. "There is definitely a war between companies that want to target these [top] students," said Rachele Focardi-Ferri, a senior consultant at Universum Communications, which conducts surveys for companies.

Rothberg agrees. Virtually all large companies offer career-relevant work in their internships, he says, because employers understand that failure to do so means "they will not be able to recruit those interns to work for them upon graduation."

And recruit they do. The National Association of Colleges and Employers (NACE) reports that last year, 53 percent of interns joined their companies as full-time employees upon graduation.

So what are companies in this hyper-competitive battle for talent to do? And how about motivated students who want the real deal? They can start by looking at internships that deliver on responsibility, internships that treat students like full-time hires and allow both the company and the student to see if they suit each other.

To find these top internships, Fortune asked people with full-time jobs who nevertheless devote a good portion of their time to the internship search. These included Samer Hamadeh, co-author of The Internship Bible and co-founder and CEO of Vault.com; Camille Luckenbaugh, research director of NACE; and Rothberg.

Here are the nominees:

Hanging out at "Bill's" place is one highlight of the summer all Microsoft interns can brag about. But since company policy is to give interns the same work as full-time hires, students have plenty more to show for their 12 weeks than a barbeque with the world's richest man.

Isabel Adler, a graduate student at the Technology University of Delft in Holland, was a program manager for MSN Messenger last summer in Redmond, Washington. She and her team developed Music Mix, a feature that allows chat buddies to play songs simultaneously and build playlists together. Adler's job was to make sure the feature made it into the next release; today, Music Mix is in eight countries and is one of the most popular features on Microsoft's chat program.

University of Illinois senior Matthew Loar explains the appeal of an internship with the software giant. A computer science student, he has coded for classes and done many projects for various organizations. But after developing a viewer for a new Microsoft document format that will be included in the next release of Windows, Loar concludes that there is "nothing that can fully prepare you for coming to Microsoft and working on real-life shipping code."

For University of Wisconsin-Madison sophomore Megan Williams, a typical day can be talking up retirement plans and executive benefits with the owner of a bread company, or conference-calling with consultants and a lawyer to create a special needs trust for a woman who wants to help her disabled grandkids.

Williams is just one of around 1,500 students annually who undertake this intensive, usually year-round internship in insurance sales. To prepare, students must pass a state insurance exam and undergo company training. Like full-time representatives, they make cold calls and pay visits to prospective clients to get their business started.

Mark Kull recently signed on to work full-time after three years as an intern. The compensation for the internship is a $1,000 stipend plus commissions, but self-motivators can make lots of dough. Kull, one of the highest achievers, doubled his pay to $13,000 by the end of his second year.

"Your success or failure is solely up to you," he says.

In an industry notorious for coffee-fetching and copy-making internships, the same academy that puts out the Emmys also offers a new breed of Hollywood learning.

Each year, about 32 students survive a grueling screening process - an essay, four letters of recommendation and an on-camera interview - for placement at media giants like Fox TV, E! and The Disney Channel. Once on board they do what full timers do and even get paid for it.

Juliet Hutchings, a documentary intern at Discovery Times, is writing and associate producing different news clips that the Discovery channel will air between shows.

Scriptwriting intern Abhishek Kambli brainstorms with writers for the show South of Nowhere, and although he cannot write because of guild regulations, he pitches his ideas and gives feedback on the script along with the rest of the writers.

Is there a catch in Beverly Hills land? There were 777 applicants this year. As Hamadeh puts it, this internship is harder to get into than Harvard.

The customer is king, and Anthony Snyder knows it. The senior from Northern Illinois University and Enterprise's roughly 1,750 other interns have full authority to make disgruntled customers smile - by giving them specials like a price knock-down, a vehicle upgrade or a free day rental - and all without a sign-off from the manager.

Interns, just like full-timers, pickup and drop off customers, wash cars and call back renters to make sure they are satisfied with their Enterprise experience.

The average pay is only $8 to $10 an hour, but with a 50 percent conversion rate of interns to full-time hires and a program that grooms hires to become branch managers, this internship is a good opportunity for anyone hungry for responsibility.

For heavy-duty client interaction, look no further than Deloitte & Touche. Interns at the professional services giant often work on client cases with a team of associates and partners.

Chris Grashoff, a student at Harvard Business School, is handling postage this summer - but he is not licking stamps. The consulting intern and his team are identifying ways to reduce postage costs for a top 10 U.S. bank. To get at the heart of the problem, Grashoff travels to a different city each week to interview employees.

Audit intern Luisa Betances, a senior at Fordham University, is working on financial statements with her team for a global investment bank this summer. She will return to Deloitte full time when she graduates in a year, Betances says.

According to Deloitte national recruiting manager Jennifer Carmody, about 81 percent of interns entering senior year start their career at Deloitte upon graduation. Now that is a number every company could use some consulting on.

As the summer winds down, Rothberg has one final piece of advice for students trying to decide among several internship offers next year: take the one that gives greater experience and responsibility, even if it is unpaid. The money will come very quickly after graduation if a student has solid internships under the belt, he says.

Of course, some students - like this writer's classmate Moitra - are lucky enough to have an internship that offers both the work and the money.

Cathy Xiaowei Tang and Ankur Moitra will be seniors at Cornell University this fall.

_______________________________

More on careers:

Best Jobs in America

Latest from Fortune's Ask Annie: Trading a raise for flex-time, and how to get over office-party jitters.