I love my aspire one (but not the linux that came with it). I have the 8GB SSD version and picked up a 6cell battery for it which gives a battery life of about 6 hours doing web surfing / streaming / whatever.
For me, the key concern in purchasing a netbook was the keyboard, and the A1's is non-crippling and has properly laid out arrow keys.
At the moment, I'm trying a new OS on it every week or so, trying to find what works best.
I just got an acer aspire one, and I like it very much. Lightweight (about 2.5 pounds), good battery life (my model came with a 6 cell, which I recommend), nice screen and keyboard. Mine has the 160 GB hard drive, 1 GB ram, and comes with XP, too. For $379 at Buy.com. Not bad. Wireless Internet reception's not bad, either. It'll pick up about any hot spot.
My runner up, when I was doing my own research, was the MSI Wind. It has the 10" screen, a really comfortable looking keyboard, and even better wireless internet, but it's a little heavier (around 3 pounds), with somewhat less battery life (3-4 hours). It's also a little more expensive, at about $400. It depends what's most important to you. I went for less weight/longer battery life myself, over slightly bigger screen/keyboard and better WiFi, everything else being equal.
Now, my dream machine's the soon-to-be-released Sony Vaio P... 1.5 pounds, gorgeous design, up to 128 GB Solid State Drive and 2 GB ram, even clearer screen, screaming WiFi. Only problem is it starts at $900 (on up to about $1500 for top end specs). But if money was no option, that's surely what I'd get.