I think Froboy is on the right track with his build. The AMD X2's will give a lot better value at that price point than any Intel chips.
If your brother will not be running Vista, he could probably do just fine with 1 Gig RAM. Also, you can usually find better deals on 19" LCD's in the circular ad's at places like Best Buy, Circuit City, etc.
If he doesn't need a burner, you can save another 15 dollars by just getting a DVD/CD Rom drive instead of burner. Newegg has several DVD Rom drives for 17.99. I'm doing a build for our 11 year old son, and just putting a reader in it. If he needs to burn something, he can use my computer. I doubt he'll need that functionality often though.