As a practical matter, it will be a while before I jump to 3.0. I am almost entirely on Rails 2.3.5 and Ruby 1.9.1 and that is working for me. Really it is a tradeoff between working at 100% speed right now or spending some time migrating to better tools.
I've pretty much switched everything to Ruby 1.9.1 and the first Rails 3.0 beta. Works like a charm. That's why I was so disappointed to see the 3.0pre2 rely on Ruby head rather than current Ruby stable (1.9.1).
As a matter of general principle I agree with this, but I've had so many problems with 1.9.1, I moved to 1.9.2-pre, and it's been working a lot better.
