That's not a lot of guidance given that there are any number of options, and no real way to tell which would be "best" for you.
Do you care what OS it runs? Size? Weight? Price? Airs are expensive, especially given their specs, but if you really want OS X and a lightweight machine that's sort of the way to go. (Although the Macbooks are due for a refresh soonish--you might want to wait that out and see what comes of that.)
If you don't care what it's running, you can probably get a machine running Windows 7 for a few hundred bucks in the near future. Given that all you want to do is surf the web and edit text, just about any machine you'll find will be powerful enough for your needs.