here's the link for fro youhttp://www.w7forums.com/windows-7-64-bit-vs-32-bit-t484.html
if you not going to use older 16 bit software & software's which has no more in development ,
then you can go a head to use 64 bit,
for that you must have new hardware's & enough GPU..(what the config you have)
most of today's software 32 bit software's works fine with 64 bit OS..