I have bought and sold many a MacBook Pro over the past several months... it's actually a nice way to make some extra cash while in Grad School!
In November I bought a 13" 2.53 model for $800 on craigslist and sold it on ebay for $1549 (it did have a lot of accessories and software).
Two weeks ago I got a 2.53 13" (battery has 3 cycles!) with the newest Airport extreme for $1100 after bing cashback. I then sold the airport for $129 and I'm currently selling the MBP on Ebay... hoping to get at least $1350 out of it.
This week I got a Unibody MB for $500 on Craigslist, it will be up on ebay soon. A couple of months ago I got the MacBook Air in my sig for $1000, but I am keeping this one.
Overall, it's pretty amazing how much people are willing to pay (even for used) Apple laptops on ebay. I typically trust mac2sell.net for my values, but sometimes ebay prices are even higher. I think bing cashback and other promotions have something to do with this, but as a seller, I'm not complaining.
That was not what I paid for mine. That was my guess on how MXChristian11 got his for $800, and I still figure it was something along those lines.
If you want to know what I paid, look at the first page; the amount does include taxes.