I use an 80 gig on my home machine. It's a pretty good sized drive. Its not too big and not too small. I'm looking to upgrade to 2 74 gig raptors and put 'em in raid 0 and use the 80 as a backup. On my servers where I work it really varies on what the application is Im using the server for. On my 2 DNS machines, I use a 120 gig drive each. My main server that I use for storage, I have 4 120 gig drives that are hot swappable. Lets see.... I have so many other machines, I loose track. Anyways, an 80 gig is probably just right for whatever application your using the computer for.