Only if it's a later model USB keyboard. The "apple" key will be your "windows" key and the "option" key will be your "alt" key (or vice versa).
There is no functional difference between Apple keyboards and any other. For that matter virtually all Apple hardware is PC compatible except for the motherboard and CPU. In most cases you could simply convert your Apple Macintosh computer to a fully functioning PC simply by swapping out the motherboard and CPU.
Graphics cards are more complicated because even though they are identical they use a different ROM so they would need to be flashed. I have a PC video card in one of my older Macintoshes that I flashed to work on the Mac. Such mods are questionable and not always possible even if you can locate a suitable flash utility.
I picked up a pair of identical PCI USB cards once and with no modification I dropped one into a PC and the other into a Mac. They both worked fine with the correct drivers installed. RAM, hard drives, opticals, externals, should all work on either platform.