I used an Asus Transformer TF101
tablet my first semester for note taking. The included note taking app is pretty cool and you have the option of inputting notes via the dock/keyboard or through the touchscreen. The tablet/dock combo can be found on eBay for ~$230.
I would steer clear of netbooks. You can usually find better specs in a small laptop in the same price range.
I think if all you want to do is take notes, a tablet is what you're going to want. Most well-know tablets are plenty fast for word processing, internet browsing, other basic tasks. You'll also likely get better battery life. The only downside is that you can't install Windows programs. Most tablets will be able to view and edit office documents either out of the box or via an app, however.