If I was in your shoes I'd probably set it up as dual boot with XP. If you are never going to upgrade the ram then 32 bit Vista will probably run faster for 32 bit apps since you won't be using WOW.
I'm not familiar with the programming tools you mention. I know VC++ 6 is very finicky and insists on putting stuff on C: drive even if you install it on another driver letter. So if you do go with a boot manager you may want to leave all your partitions visible to each other. I've had no problems putting XP and Vista or W7 on the same drive and dual booting. Then again, you need one or the other product disk to fix up the boot after installing XP. (google "ntldr missing or corrupt" error msg to see how to fix it.)
I'd say the little bit of ram doesn't matter. The only thing is you may want 64 bit if you think you might put like 6 or 8 GB ram on the system.
I'm running Vista64 SP1 on a quad core with 8 GB ram and it's very smooth.
Edited by MilesAhead, 31 May 2009 - 05:27 PM.