What I actually do for a lot of games is create a folder in C:\ called "Public" (or "Applications" or whatever you want to call it), right click on it, go into properties, security, and give "Full control" permissions to every group/user name listed. I install any games that were made before around the time Vista came out (Vista introduced UAC and the VirtualStore) in this directory. Basically, any game that has issues with permissions. I also put any games that don't have an installer in this directory as well, as there's generally no good default place to place these and this is as good of a central location as any.
http://i.imgur.com/A0aEaff.pngMore advanced:
If you don't want to screw around in the "Security" tab and you don't mind programs only working on your Windows user account, you could instead make a folder like "Applications" in %userprofile% (C:\Users\<yourname>\). Or you could do it in C:\Users\Public and then it would be accessible to all users. There's no standard way of doing it and these would all work basically the same, it's just I find it's easier to find the C:\Public directory (plus it works with REALLY old games, like 1990s era or earlier, that have issues with long path names or spaces in path names).