sorry, I meant the new iMac. I think this Thunderbolt port will prove out to be really good. Problem is, what's out there that can utilize it?
So, perhaps waiting for Lion and more periphials to come out before getting it might be the better idea. Especially in the hard drive area. That's where it'll come in handy.
Best scenario: get the...wow, just seen the price of a 256GB SSD card! Yikes!
But, since this is a work machine that should last you 5-6 years at minimum, I would recommend this setup:
21.5 inch iMac
2.7GHz Quad-Core Intel Core i5
4GB 1333MHz DDR3 SDRAM - 2x2GB
1TB Serial ATA Drive + 256GB Solid State Drive
AMD Radeon HD 6770M 512MB GDDR5
You want something that will run fast? There you go. And then later on get say a Drobo or whatever that utilizes Thunderbolt.
And by getting the smaller one, you can get a Apple LED Cinema Display (27" flat panel) as a second monitor. I think having 2 would be better than one large one especially for apps like Photoshop.