I will say that the Apple keyboards are very very pretty, but they just aren't great for typing. For me, there is not enough key travel and they are just completely uncomfortable. They are not very ergonomically designed. So, if you do a lot of typing, I'd look elsewhere. My personal favorite is Logitech. Keep in mind that you can buy a keyboard with a Windows key, just be sure that it has Mac drivers (the Logitech website will tell you). The Windows key becomes the Command key, and F12 pulls double duty as an F-key and the eject key (if you hold it). Also, the button that pulls up option menus on Windows doesn't do anything on a Mac.
I've used 3 Apple keyboards (the old white one, the new aluminum wired one, and the new aluminum wireless one), and none were very comfortable to me since I have used much better. Even though my Logitech G19 is not really ergonomically designed, I can type an 8-10 page paper on it quickly and painlessly. I can't say the same about my Apple keyboards or my Macbook Pro's built in keyboard.
If looks don't matter so much to you as comfort, get a different brand than Apple. If you like the looks of the Apple keyboards (they are extremely good-looking), by all means go for one. You won't be disappointed unless you use it for typing large amounts of text all the time.