Not long ago I install Windows 7 32 bit and the result is good.
Since my processor is capable for 64 bit operating system, I will give 64 bit a try. It is newer technology which allow more that 4GB RAM to be used. 32 bit OS only allow maximum 3.0GB RAM to be used.
This time, to save DVD, I use my 4GB pen-drive as a DVD. It was done using WinToFlash software. And, I install my 64 bit Windows 7 a lot faster than using DVD.
Trying 64 bit, I notice less difference in performance, and very little software incompatible (Can't use Sandboxie only). Since my laptop is not old, I have all my drivers download from Windows Update.
As for games, there has no improvement for me. I think there are some improvement for certain games, and vice versa. I see in several forum saying that RAM usage is higher, but for me, I see no change in RAM usage in idle compare with 32 bit.
As a conclusion, I recommend 64 bit for users that has higher than 3.0GB RAM. Else, there are no advantage using 64 bit except very little program incompatible.