The newest generations of ultrabooks (including Macbook Air) and Windows 8 tablets (especially convertible ones) are going to start eating iPad sales by year's end.
Greater functionality and power (which is what most netbooks lacked) in addition to lightweight portability are attractive selling points to people who need to work on the go, or who want higher end gaming than the iPad or Android tablets can deliver.
I want a Zenbook or the new Samsung Series 9 so bad. There's a healthy amount of competition in the ultrabook category early this year, and I'm hoping prices continue to drop from just below $1,000 to below $800. I wouldn't even consider a tablet at that point.