To answer your question about older laptops, I would say that apart from an outdated CPU (which is not an issue to u), you'd have to deal with pathetic battery life and heating issues. The NC10 is ur standard netbook but with exceptional battery life ~6-8 hours, moderate usage).

Also, if you're gonna be using it for normal activities sans gaming, any standard low-budget laptop should fill your need. Did you check out Acer and Compaq? As for the notebooks, an Aspire One is pretty cheap albeit weak (even by netbook standard).

Overall, I usually prefer new stuff over second hand. But that's just because I don't really trust people/like second hand stuff.