I just got a second iMac, and transfered stuff from my old 20" to the new 24". I do not think the model matters, just what OS version you are running. Anyway, I was in Leopard... when you run MA, you get options to copy Apps, User settings and some other options, so you have SOME choices about what to move. Apps should be no problem, and my keychains moved over.
I would do it, and check it out for a couple days to make sure you got all you need. You can use a USB key if you missed anything (I was not missing a thing!)