I'm just thinking a 40gb hard drive will be filled up really quickly with music, games, etc.
But I'm going to have 330GB total. Not only that, but I've had these same two HDD's for like let's say 5 years. I've only used up a combined total of 25.54GB. I honestly don't even need to include a HDD on this build, but I really think I will regret it if I don't since this computer will probably make me want to do things that will require more than 80GB total.