FWIW, I have a first-gen Intel mini - Core Duo, only 1.66 GHz.
It's still going strong, now performing as my office server (after two years of being my primary machine), running 24/7 quite happily. Compared to my early 08 iMac 24", it's a tower of reliability. It never gets hot, it rarely crashes, it just does what it should.
I'm actually thinking of going back to a mini next May after my iMac comes of corporate lease. I've had the usual iMac issues of overheating, screen persistence problems and a (less typical) total logic board failure.
Given the power of the current Minis is good enough for anything short of HD video encoding (not that they won't do that, just that it will take quite a few hours), I think you'd be on a winner.
Also, you can get a high-grade Dell screen and save yourself significant $$$ over an Apple display.