Many kids have their own computers nowadays, but if your son or daughter is due for a well-deserved upgrade, there's now more to think about than just a Mac or a PC.
With desktop models, notebook computers and netbooks to choose from, it can be hard to select the best computer for your teen. We've reached a point where computers are getting smaller and more lightweight, while phones and other electronic devices are becoming more multi-functional. Your best bet is to sit down with your teen and discuss the types of features he needs relative to the costs involved. There are lots of bells and whistles available, too, like touch screens and built-in TV tuners that make current generation computers very enticing, but like most electronics, if your child doesn't need the functionality now, when he does, it may be time for another upgrade anyway.
Check with your child's school to see if they have any recommendations, too. As a rule of thumb, desktop computers will be less expensive for the features you get, like a large hard drive. Netbooks seem like a good choice because they're downscaled and very lightweight. They can also be a bargain at less than $500 (often around $250), but most lack optical drives, so there's a trade-off you'll want to consider seriously before you buy.