Greetings fellow duders, 
Just got a question. I just got a new macbook pro, I installed steam and a few games from steam on it. I'm thinking of dual booting with windows so I've got access to a wider range of PC games. I was wondering if I buy Windows 7 and download steam again will I be able to download those games again at no extra cost? 
 
I'm sure someone here can help me, thanks in advance!

If you buy games on Steam they are linked to your account. You can install STEAM and download each game at no cost, yes. It isn't like itunes where you have to recover your purchases or anything like that.

Once you buy it,you can download it and install it on anything (as many times as you want)

Only "Steam Play" games can be played on Mac and Windows with no additional purchase needed.  However, I believe at the moment all the Mac games support this.  I just wanted to mention it in case they add games that don't support it in the future.

Sounds cool guys. I figured it would be ok, just needed some confirmation. 
 
Even if it doesn't work I'll only miss out on $20USD so it's not a huge deal anyway. 
Looks like I'll be ok anyway.

Just make sure you use the same Steam account details and you can play your games on any computer.

It works. I have my steam games installed on 3 different computers, one of them being a mac. They all boot and play just fine.