In addition to the big iMac announcement, Apple also made a few lesser but greater iLife feature introductions that could have a big impact on iPhone users - those who use Macs anyway.
iMovie '08 now enables video to be encoded and formatted for iPhone's native screen resolution (HVGA). So now you can view your home videos on any iPhone, and share them with other iPhone users.
That's not all. iPhoto '08 offers a new .Mac Web Gallery service for uploading and sharing photos from a Mac, PC, or...iPhone! So iPhone users can now upload images captured from the phone right to a .Mac account. Pretty nifty, eh? Of course you'll have to pony $100 to purchase a .Mac account, and oh yes, a new iMac wouldn't hurt.
So goeth the upgrade treadmill.