Computing power-wise there are few machines that can't do the job for most people. I recently had a friend get the ASUS 1015B[1] for $289. For everything he does (he's not a developer, rather a policy wonk) it works just fine. He loves the form factor for travel, weight, everything.
But the problem with MBA, netbooks, and laptops in general is that they're less productive for some classes of work. Generally due to the display size/resolution. I find that even a 24" dislay is not adequate to really work at full steam. I need at least 2x24" when doing serious dev work. I can work on my laptop in a pinch, but its like writing a long email with T9. Sure, you can do it, but its not the way you like to operate.
But the problem with MBA, netbooks, and laptops in general is that they're less productive for some classes of work. Generally due to the display size/resolution. I find that even a 24" dislay is not adequate to really work at full steam. I need at least 2x24" when doing serious dev work. I can work on my laptop in a pinch, but its like writing a long email with T9. Sure, you can do it, but its not the way you like to operate.
[1] http://www.asus.com/Eee/Eee_PC/Eee_PC_1015B/