Netbook usability..?

My old computer bricked itself beyond repair a couple weeks ago and I need a replacement. I'm on a real tight budget at the moment, so I considered getting a netbook. I figured I could probably stretch the $350 for one of the new Acer Aspire Ones (AOD150 models). But I've never used or even seen one of those things up close and I'm a little concerned.

How are their usability? Is the size and performance acceptable for using as a primary machine? (I'll be browsing the net heavily, word processing, watching videos, listening to music, perhaps playing some old 2D games, and messing around with Linux on a spare USB hard drive). Are they overall comfortable to use over extended periods? And is the screen large enough to reasonably watch movies on it?

Thanks.