thats a hard question to answer. it depends on what how you are using your pc. if you are building a gaming rig, a 32 bit system will be fine. because most games don't use more then 2 gigs of ram. if you are encoding video or using photo shop then you should go with a 64 bit system be those type of applications need more virtual and physical memory.
I have a 64-bit windows 8 HP Pavilion g6. I mainly use it for gaming, movies, moddding, and browsing the internet. Works great. I would definitely recommend using it.