Hi, I'm looking at buying a new Mac, iMac specifically. I was wondering if I should get the iMac 21.5" with 4GB of RAM, or build to order 8GB 21.5". I currently have a Mac Mini with 4GB of RAM with a Core 2 Duo 2.53GHZ. It runs a little more slowly with Lion and has a lot of trouble with iPhoto and Garageband. I would use it for photo editing, full screen apps, email, web browsing, GarageBand with multiple tracks and extended desktop. Which iMac would be best for me?