If you are an overclocker (or ever want to be, which anyone on the forum would recommend with these new Intel CPUs [i7-2600K/i5-2500K], as they are capable of 5ghz on air cooling) be sure to get the i7-2600K.
Honestly it's overkill for most GPU setups out there, but it's easily the world's strongest CPU for gaming. (the i5-2500k is also great for gaming, as most games don't benefit from Hyper Threading)
One thing to remember... is that all 3 options you're weighing would result in a very fast system that you would probably have a hard time perceiving a performance difference. For gaming, the GPU would be much more of a factor... and all 3 will scream for general computing.
... but ... you want to get the best machine you can for the money you're spending...
Between the two i7s, assuming comparable pricing (which is what's generally predicted), the 2nd generation chips seem to be faster, so unless the maturity of the chip and chipset is an issue, that would drive me to the 2600.
Between the AMD and Intel, I think the performance edge is going to go they way of the 2600. The 1100T is showing up at Newegg for $270. If you have a Microcenter nearby, its looking like the 2600K will be in that neighborhood (with in-store instant rebate)... so if you can take advantage of that, I'd say Intel. If you can't, then it might be roughly a $100 difference. Motherboard prices might factor in, but that $100 out of a $500-600 cpu/mobo choice is about 20%.... or much less of a 'whole system' slice of the pie. You may see the difference, but $100 in your pocket is something too
If you're an AMD/Intel fan, have power draw concerns, like a certain motherboard, etc.. that all can figure... Again, any way you go... you'll have an excellent system.
over all I think I might go with the Phenom, mainly because it is still a strong chip, makes the whole rig a fair amount cheaper and I've decided that if I get the 2600K now, it will end up costing me a lot more to upgrade when the new chips come out later this year/early next.
Thanks again, gave me a lot to think about to come to my decision.