it has a bigger operating system
What he said.They're both from the current...
So you are talking about a $337 difference.2.8 GHz = $1549 + tax
3.06GHz = $1899 + tax
My suggestion. Get the 2.8. Upgrade the RAM to 4GB if needed.
Save the rest for a new (another iMac) 2-3 years from now. At that time you can sell your 2.8 iMac for a decent price.