hi 47ronin,
(about the previous imacs, haven't checked out the new flower power stuff).
the easiest way to get sound into an imac (not taking the 1/8" mic input into account) is through its USB-ports using a device like the Roland UA-30. it's a very basic device that will translate signals from mics, guitar, a mixer, your stereo or anything else with RCA phono jacks, optical/coaxial-S/PDIF(a digital connector found on CD-players, DATs and some portas and mixers). it's small, convenient but more of use for people who want to put tape recordings, vinyls etc on their imac. depending on your demands, check out that one or Tascam US-428, a thingy that will allow you to control your recording software off screen like on a regular mixer.
US428 also uses USB, comes with rec software, and is much more of a recording tool than UA30.
There's tons of stuff out there, but if your VERY serious about getting in to recording on a mac, i would recommend a higher end mac. when you buy an imac, there's not much you can upgrade besides the RAM and, if you're a bit handy (apple will tell you not to try!) , the hard drive.
one other thing, the hard drive in the imac is pretty slow for recording/playing back music that is more than 8 tracks, and while you can upgrade size of your HD, you're stuck with the same slow speed (5400rpm - you want at least 7200rpm), the imac doesn't have a fan that can cool a faster hd. you might be ok, but on other hand - you might not... i'm not sure about the new imac's HD-speed.
if your demands are not too high on performance, the imac will make a good recording unit.
hope this helps and good luck,
micmac
