Yeah, I agree -- I mean, I'm still running OS 9.2.1, which was the bestest OS ever -- it took me quite some work to hack it to get it to run on my PowerMacs, but it's worth it -- I just don't trust any of that newfangled OS X stuff.
Why update?
For starters, because just with a software update, my MacBook Pro suddenly runs and feels up to twice as fast than previously - that's good enough for me, for spending $29.
As an aside, though, it's worth spending the money on the Mac OS Boxset, which includes iLife and iWork as well, and basically gives you OS X 10.6 at no charge at that price.