well, if all I had was $199, I would go for something like this....however, I am generally tempted to notch it up just a wee bit.
the athlon xp is a bit long in the tooth, but, its at the sweeet spot for best performance/dollar. I got caught up in the 'mobile barton' overclocking craze myself...but I saved a bunch of money and have a fairly fast system...spent less than 500 total on my computer.