I have to choose between installing in Program Files and Program Files x86. The game is 64 bit. Does it matter where I instal?

Solution
No it makes no difference whatsoever. x86 is for 32 bit software technically, but you can install software anywhere you like. It's just for your own reference nothing else.
You should not have to choose where to install. However, you do choose the type of installer. So yes it does matter. Most installers are 32-bit (x86), but if it says 64-bit (usually ending in x64) in the installer, then it will install there. Otherwise, it is going in the x86 folder.