Wow - what a difference a new hard drive makes! My 3+ year old iMac 20" 2.16 had become incredibly sluggish. Applications like Word would take 15-20 seconds to load, I'd have to wait 15-20 secs to open files, it was awful. Repeated attempts to wipe the drive and reinstall OS 10.6 didn't help. Turns out I had an "invalid node structure" error on the internal drive that kept recurring. I was this close to buying a new 21.5 when I decided to invest $77 in a new 750 GB drive and $55 for installation. And the results are unbelievable. Everything is just lightening fast again, from app startups to browsing to photo editing. $132 just extended the life on this computer for at least another year. Anyway, thanks to the folks who tried to help me fix the problem with the old drive and especially the people who said "just get another new drive".