Er.. yes and no. My own site(s) for sure ie the ones that it is not a big deal if a few glitches crop up. But for client sites I am going to wait a while to ensure there are no 'gotchas'. Some of these sites I plan to rebuild rather than upgrade, using the opportunity to give them a makeover and use some of the 3.0 features especially ML, templates etc.
Looking at my sites (about 30)I was surprised to realise just how few 3rd custom modules I use (I have a few of my own for specialised use). A good image gallery and that's about it.

I upgraded my personal website this afternoon. Just could not wait any longer. :)

Many pages generate an error, and I'm trying to track down the issue now.