So you should have saved some time and called Reboot first since you aren't going to listen to me.
I still think you should go new. Thunderbolt won't "mature" any on the iMac,at least not for a long while, but new periphials will be coming out. In the meantime, you will be stuck with last years model with no chance of using thunderbolt at all...until you upgrade again.
New ones are only $400 more. Considering that you would/could use this one a LOT longer than the previous model because of TB....just saying.
That 27" one is out of stock...did you get the last one?
And wait, isn't that refurb one a single processor? I don't see any mention of duo/dual/etc on there.
You will want at least a duo core running your photo apps.