I need a computer devoted to just photo editing. I found a Imac 5.1 with 20" screen and Intel Core 2 Duo, 2.16 ghz.
Any input would be appreciated.
It should work, but won't blow you away. i7 with 16Gb of RAM on the other hand is a beast, it would certainly be chewing through anything you throw at it, but it's probably more than you need. I run everything on an i5 Quad 27' with 8Gb RAM and it's plenty fast, hasn't crashed yet, not once. If this one is what fits your budget, I suggest maxing the RAM on it and seeing what the video card is like, it may well be what works for you.
I made the switch to Mac when my PC kept crashing with ... photoshop... I am sure there are people out there who use PC's just fine, for me Mac works better.