Im looking at buying an iMac (would like a mac pro but space contraints say no). Is it possible to use a second monitor in extended desktop mode with an iMac?
Yes, Mini DVI to DVI on the second monitor. The only concern can be the cosmetic appearance if your the type who care about the two monitors looking the same.
I have a 20-inch apple cinema display hooked up to my iMac 17-inch and I love it. I only wish the power brick had a longer cord so it doesn't have to be on my desk behind my iMac.
22" samsung next to my 20" white imac. Yeah, it's kind of a ebony and ivory effect, but I'm okay with it. I'm not about to go out and paint the outside of my monitor white or anything.
Considering how easy and cheap it is to add another monitor, I'm wondering why people pay the big bucks for the 24 inchers.
My 20" Aluminum has a Polyview 17" LCD (lifted from my previous PeeCee) tethered via Mini-DVI-to-DVI cable. Works like a charm; I haven't had to use Spaces yet.
OS X's Display Preferences even let you appromixate your multiple-display arrangement visually so that your mouse moves intuitively between screens, which is really handy for those monitors that aren't the same height as the iMac's.