Got lucky with mine, though it was expensive for what it is. I've got a 2GHz Core 2 Duo system stuffed into a fairly lightweight 12" case, with 4+ hours of battery life. Useful. However, netboks have much better battery life, and when you take into account that I was running on low power all the time to conserve the battery, they're also more powerful in a way.
However, when you look at the price of laptops and what you're wanting it for, it might be better for you to get a desktop and netbook. Newer netbooks can top 14 hours of battery life, while still saving you enough money to buy or build a decent desktop to do the fun stuff on.