If the OP is looking for something in Netbook size range the 11.6 MBA and Samsung Series 9 machines are, as others have said, excellent but they are in the $900+ range. Sony (YB series) HP, and Lenovo (130e) also make 11 inch class machines that use AMD processors and graphics. Speed is adequate for office tasks and they can easilly play HD video. Should be able to pick one up for about half the price of the MBA.

If the OP is willing to consider a used or refurb machine a Sony Z can be found for not much more and these are fully powered machines. Likewise a refurbed Lenovo X 220 12.5 with an i5 sometimes goes for $650.

Short of 3d gaming, photoshop, or CAD, there isn't much these machines can't do.