Are the 17" monitors CRT or LCD?
I'm facing the same thing you are, though I have the 24" lcd now. Back in the day I had dual 17" CRTs.. and one 24" is much better, because the 17"s were crt.
I'm still getting another monitor. You will have plenty of room with just one 24" because it is basically two monitors, but I need another one personally. I think I'm going to get a 19" or 22" widescreen to go with it. Once you do dual, you never go back.
I say if your monitors are CRT, get the 24". If not, get the 24". It's alot of room and awesome with games and movies.
The prices go up and down here, I got a 19" ws for my dad at 99$.. they jumped 10. And you get free shipping most of the time. My 24" is awesome and about 8 months old. The 19" is about a month old and awesome.
*Caugh* Tri-monitors *caugh*
My set up soon will be two 22" ws monitors on my desk and a 24" ws mounted to the wall on a swivel thingy! That would be awesome! For now I must work on surround wound.