I'll be buying at least one, even though it won't support any of my TVs full resolution. I see it as a great way to control my iTunes library (Videos, Vodcast, Music) from my other rooms. It's only $299 - so even if it just turns into a toy for gatherings it'll be worth it.
I must say though, I'm shocked at home many people complain that they would need to update their TVs. I can see people having the old 1080i TVs, but having a TV that doesn't accept the old component hook-ups, come on people! If you can't afford a decent modern TV, you don't need to be dreaming of owning an Apple TV, you need to be taking night classes to increase your skillset and increasing your income with a better paying job. Flipping burgers at the local fast food isn't going to afford you extra toys like the Apple TV. Just my 2 cents - I'm sure many will complain how I don't understand how hard it is to go to college, how all the "good" jobs are taken, etc.
But back to the Apple TV - it's cheap, it looks like it's cool and easy to use, would make a great interface from the computer to your TVs during gatherings or parties at the house. What's not to like? If you want a DVR buy a DVR - don't moan about how expensive a $299 box is that doesn't do all these other things.
James