So I cant make up my mind. I can either buy a 15" MBP for $1799 or a 27" iMac for $1699. You would think this would be a simple decision, but its not. I dont need the portability of the MBP but it would be nice to have. On the other hand the 27" imac looks amazing but is much more difficult to stick in a backpack. I'm not a power user.Although i'd like to learn more about Macs I must admit that mostly I'll be using this for websurfing, music storage, email and some entertainment. Any suggestions? One more dumb question. If I buy the MBP and let it run for hours as my main music machine will this have a negative effect?