27", i5, 680m
I will upgrade the RAM myself to 16GB within the first year, and perhaps to 32GB in a few years as prices come down and the machine starts to feel long in the tooth
On the storage side, I'm very undecided. I want to see the price difference between the 768 SSD (doesn't look like they are offering 512) and the 1TB Fusion. If the pure SSD solution is sub $500 extra, I'll probably go that route. It's architecturally superior with less points of failure. A bad HDD killed my 2007 iMac before these came out, so I'm very interested in reducing that risk factor.
I intend for this to be my primary personal computer for the next 5+ years. My 2007 lasted 5 years and 3 months before the HDD issue. Poor thing.