So I am looking for a desktop to replace my Macbook and am looking at the high-end Mac Mini and the entry-level iMac. I have a monitor and a wireless mouse and keyboard I would use for the Mini. My gf uses Second Life, will the 9400M be powerful enough for Second Life? How much more powerful would the 4650 GPU than the 9400M? Is the iMac worth the additional $400 to $700?