I got an HP Mini 1000 and couldn't be more fond of it. I opted for it for two reasons.
1: It has far-and-away the best keyboard of any netbook I tried (I have fat fingers and wrote a NaNoWriMo on it--if that's not testimony to a good netbook keyboard, I don't know what is). It's nearly a full-sized-keys keyboard (97%, if I remember correctly) and the layout of non-alphabet keys is comparable to or better than any other netbook design I've seen.
2: They sell some of them with either 8 or 16 gb solid-state hard drives, which has been a boon--the only moving parts in the entire laptop are the fan and the keyboard keys, so you don't have to treat it fragilely. Mine's been knocked off the bed, tossed into airport screening bins and then shoved back into overstuffed backpacks, even been dropped onto a linoleum floor hard enough to knock the battery pack out, and (knock on wood) it hasn't suffered a bit.
The weight is also good--it weighs next to nothing. It boots quickly--maybe twenty seconds from fully-off, 10-15 from hibernate, nearly instantaneous from standby. The only gripe I'd have is that the battery life isn't that great--two or three hours if you've got the screen brightness at normal and are using wifi. Then again, that might be par for the course, especially since I've had it for more than a year now, and the battery life *does* dramatically improve if you turn off the wifi or lower the brightness.
I'm not sure if you'd be able to find one for $300; on Amazon, the current models are going for more than what I paid for mine a year ago, which was around $300, if I recall correctly.
Good luck, and I hope this helps!