I graduated from law school in 2002. Rather than going into practice, I decided to go to graduate school in psychology and ultimately do trial consulting work (I've got another year or so of school left) but many of my friends from law school went on to big name, big money Chicago firms. Of the 10 or so people I still keep in contact with, all of whom went to big firms, only three of them are still at what I would call a lawyer factory (and one of those switched firms). The rest have gone from a giant firm to a more medium or small sized gig. Sure, the money at a big name is awesome, but without time to spend it, what real good does it do for you? They decided that they'd rather have more time for family, friends, and recreation on a still very comfortable (just not obscene) income.
One of my friends who is still at a law factory made a real effort to enjoy his earnings back when he was a bachelor (he's now planning on marrying a woman he knocked up, but that's another story...) but it seemed to take a bit of a toll on him. He had a routine for a while where he'd sleep (nap might be a better word) at the office Monday through Thursday, go home Friday sometime in order to pack a suitcase, hop on a plane, work on the plane, enjoy his Saturday wherever he was going that week, then get back on the plane Sunday, work on the flight back home, unpack his suitcase, and repack it with what he'd need to live out of the office for the next few days. Sure, spending each Saturday in Europe or similar was nice, but I think he got tired of the hassle of it all. Others who lived a less decadent lifestyle simply decided to get out while they still could.
Big firms aren't for everybody for plenty of different reasons, but they're obviously right for some people--even a few who don't just end up getting trapped there. It's something you have to figure out for yourself, so if you've got the grades, I'd recommend at least checking it out for a summer and trying to get a feel for whether it's an environment you'd like. As Special K noted, your summer there won't be very representative of a career there (and the fact that they basically blow $50k on each summer worker between salary and entertainment ought to at least provoke some suspicion...) but you'll get your foot in the door and have the right of first refusal when it comes time to find a job in a couple of years.
I know this isn't particularly insightful or helpful, but it's a decision that really just comes down to individual preferences.