Well yeah. 32 bit wondows can not use more than 4 gb of memory. But 4 gb is RAM + video memory. You may not feel the difference, if you do basic things, but if you are going to play games and do a video job, you have to install 64 bit.
I can't think of any reason why you would prefer a 32-bit installation over a 64-bit if your computer can handle the last one? For programming, gaming, but also all other tasks, I think a 64-bit-machine will perform better?
64bit it much better i think, in windows 7 most apps are backwards compatible 32 and 64. that was the big issue for me before 64bit os and then a bunch of programs would run on it. now you can run most of em on 64