I was waiting, but then I bought
I was in the 'wait' camp...until this morning, when my ancient and very battered early-2007 MBP would not do anything. Every time I tried to open a program or click on a file, etc, the screen would flash for a second and then I'd get the spinning beach ball of death. The beach ball would stay on the screen until I tried to force quit a handful of times. Nothing would open or work, I'd just keep getting the beach ball and my hard drive kept making spooky moo sounds. My MBP has been threatening to die on me for close to six months now, so I'm not terribly surprised. Its battle injuries included: gaps in the frame at the keyboard and the screen from when my aunt dropped it onto the tiles at my parent's house (it was only six months old at that point!), a 'd' key missing, a busted fan, mould behind the screen...I'm actually really impressed/surprised that I got five years' use out of it.
Anyways, I bought the entry-level 21.5" iMac today at my local Apple Store. Got it home, plugged it in - my goodness, what a difference! I am so happy and excited to be using a computer that doesn't take five minutes to load firefox! That has a 'd' key! There's no mould behind the screen! (And, oooh, It's so pretty!)
I'm glad I bought the new iMac. I would have liked to have held off until the next refresh, but my MBP had other ideas. When the new line comes out, I will probably hold off updating until the following refresh and then give this iMac to my husband (who has never owned a Mac!).
Long story short: If you need it now - get it!