Windows 7: Program Files and Program Files (x86) folders?

I noticed there are 2 of these folders in local disk C:

when installing programs, which one should they go to? Are there differences between these 2 folders?

Program Files x86 is for 32 bit applications and Program Files is for 64 bit applications. Windows is smart enough (well most of the time) to know which one they got into.

ahh ic

most programs are 32 bit right?

Most of the things you'd commonly run across on the internet are (still) 32-bit. The OS "knows" whether it's 32 or 64-bit, so it suggests the corresponding Program Files folder during app installation.

(In the interests of chaos, on a 64-bit machine the \windows\system32 folder contains 64-bit DLLs, while \windows\SysWOW64 stores their 32-bit equivalents )