A 4-month not-yet-PC Switcher here.....
I have held off buying because A) My current computer works, it's just old. B) The buyers guide recommended not buying because IMacs were due for an update and C) ALL the rumor sites were saying the IMacs were to updated "soon".
I have read others list of desired features, and other than DTphonehome's minifridge

I can't say that the lack of most of those features are deal breakers to me. What I hope for, and why I waited, is to get the newest hardware (so waiting for Leopard is not as important to me) as I can. Do I want better graphics (and/or an upgradable video card)-yes. Bigger hard drive-sure. More memory capability-OK. But I did price out a Dell at roughly the same screen size/memory/graphics card as the Imac 24" (upgrading only the graphics card on the IMac) and they came out roughly the same price. And since I am new to Mac's, the styling doesn't look old to me.........
And I personally hate Vista, and I don't want to buy an older (read XP) MS operating system.
What does torque me off about Apple, and remember, I have not dealt with Apple since I sold my Apple II in the early '80s, is the hyper-secrecy about release dates. If I had known that the next IMac wouldn't be out until July/August I would have bought one last March. There is no point waiting 4-6 months for the
Next Best Thing since once it arrives you are only 4-6 months away, probably, from the
Next Next Best Thing. And from the number of "Should I buy now" threads posted here in the last 4 months I was not alone. But no one likes buying a computer JUST before the next one is released, and from the best (un-official rumor based sources) I could find, that is what would have happened.
If Apple had said in February or March that their next hardware update would be
'after the Iphone but before school starts' I think a lot of us sitting on the fence would have purchased sooner, and those that didn't, would be in the same holding pattern they are now anyways. And that time frame would have not "locked" them to a specific day, leaving room for un-forseen problems to be solved without violating their stated release time.
That may not be how Apple has traditionally treated releases but this is new to me.