personally.. i would go with a decent laptop.. nothing overly expensive.. $900 max?
save the money for the new desktop till when starcraft 2 actually comes out, then build a gaming rig, theres really no reason to rush upgrading or even buying a new desktop atm
and really your need for the laptop is some notes at class, online, and sometimes webcam
a netbook might do your job.. but yea just my 2cents, wait till starcraft 2 comes out before actually in deciding to upgrade or even buy a new desktop