If your gonna get single core def get an amd cpu, if your going duel core to play games and run some apps in the backround I think you should get a core2duo e6400 and overclock it, it overclocks better than the e6300.
The e6300 can hit some nice speeds with air cooling, someone here is tweaking thiers to 3.5mhz, I'll be overclocking mine to 2.5-3.2 and faster after I get the drift of oc'in.
Article on oc'in >> http://forums.techpowerup.com/showthread.php?t=4097
you can find more overclocking articles in the article section of the fourms, if your interested. You dont have to OC, your dad might not want you to and you cant blame him.
It will give you more bang for your buck and people here OC thier rigs for years without any problems.
Dont forget to get a good quality psu thats guarantied to last. If you search the fourms using the search option you will find many posts on psu's.
hope my post helps you out some