Well, for all that stuff I'd say spend a little bit more $$$ and just get a regular laptop. Unless the netbook has nvidia optimus you may get stuttering video. I know on one of my friend's netbook on youtube 720p frames drop every now and again.
You can get some decent core 2 duo HP laptops for around $500. But if you're absolutely sure you want a netbook I would say check out Asus. They're leading the netbook pack in terms of reliability and battery life. You can get them for around $350.