I've always done Character Sheets in RPs, with the exception of a place called HiddenWorld. It worked well enough there, but the RPing wasn't nearly as detailed as it is here. HERE, I've done a 1x1 or two without CS, but to be honest...I prefer them. I think it's a great way to help keep track of your characters, AND a good catalogue of the characters that are in your RP. Plus, it's fun to see the characters the players come up with, and get to know them at a glance. It's a good way to get a writing sample from potential RPers too--if they don't put any effort in the CS, that may be a warning about what will happen in the RP itself. Thus far with my own, I've seen this to be true. Dervish pointed this out in another topic about RPs somewhere, and it really DOES ring true!!
All in all, I think Character Sheets are a good thing--but then, I like to delve into my characters, really flesh them out and a well-written CS is a good way to do that. idk, I think all around, CS are very useful, if for no other reason, purely a records thing. It is a real embarrassment to forget the color of your characters eyes or hair--or even mix up their name!! (Or someone elses!!)