[quote=TheLastRunaway]
My first question would be, Should I use a character sheet?
[/quote]

The simplest answer is, you should do anything that you think might help. Some writers do better when they have a plan (be that character sheets, story outlines, or sometimes even pictures and soundtracks for specific scenes). Others sorta play it by ear -- 'Seat of the pants' is the phrase people use, just flowing naturally from one plot point to the next. 

It's counter-productive to speak in generalities, but [i]generally[/i], most people wind up writing way, way more material than makes it into the final draft. Whether that's in the form of planning and outlines, or just deleted scenes -- you should expect to write lots and lots of extra stuff that isn't ultimately going to be used. So with that in mind, it's not like writing a sheet is a waste of your time. It can help you keep things organized, and that's usually helpful -- but not always. It might also make your characters too static, if you keep coming back to the same big pile 'o' facts.

I use a writing program that lets me keep several files open at once ([url=http://www.blackobelisksoftware.com/]LSB[/url]), and one of the advantages is that it's super easy to keep notes on like a bunch of characters all at once. I don't really use it for 'character sheets' in the RP-sense, but it's nice to be able to keep active notes on whatever's happening in the narrative at the time. If I get an idea for something the character might be thinking, but not saying/doing yet, then I can put it in their file and pull it out later. That's what works for me -- your answer is probably going to be different.