I wish thegradcafe would also include GMAT/GRE statistics... gradjournal only has 3 listed for the Fall 2008 applicants
Sorry, didn't mean to make you nervous about the whole thing.
But I think there is a very fine balance to be struck here... A median is that's all it is: a median. 50% fall above, 50% fall below... and to get slightly nerdy, it's actually a pretty useless statistic without standard deviation. Although if you had a good idea about the class size you could make some guesstimates.
But if you're GMAT is in the respectable 700s, then research and LOI would be more worth the effort spent. If you can, I would highly recommend you visit the professor you plan to work under. Like I said, once you sit down for a chat, they just might like you enough to pretty much overlook your shortcomings. Try to do it early though, January/February are hot seasons with everybody trying to visit professors. On my visit to Columbia I heard no less than five other people chatting on the cell phones with variations of "Yeah, I told him I was going to be in the city today... he said to drop by any time... I have my pubs with me...".