Can a netbook be my primary computer? Will it work for me?

You will be able to do all the things you mentioned on it. The downside to using a netbook to watch netflix or youtube is that the screen is very small. As long as you can get over that, you are golden. I looked into getting a netbook instead of a regular laptop too but I decided I couldn't handle it because the keys were too close together for my taste. I opted for a Lenovo that is compact, has a long battery life, is not too heavy, and has a larger screen. Obviously, the negative to this is that I paid 700 instead of the 300 you're going for. I say get the netbook :)