I have a mac and the iTunes remote lags it worse than 20-on-20 zergs in Alterac Valley. When i had keys bound to it, I ended up accidentally pressing them. If iTunes isn't already open, pressing a remote key opens it automatically. If you're in full screen mode you have no idea wtf is going on until you window it and see the iTunes bouncing on the dock asking if you want to update your iPod or someshit. If you need more reasons why mac is FTL, the default Ventrilo codec (GSM 6.10 or something) isn't supported, and you have to ask your moderator (probably guild master or officer) to change the codec to Speex (the mac version of Teamspeak is actually called Teamspeex), resulting in their thinking of some BS reason why they can't and you have to raid deaf.
The verdict: graphics cards may be expensive, but play WoW on a PC.