At least not yet. I'll probably do it in two or three weeks. Why?
Because official release date doesn't magically make the distro stable. It does, however, make thousands of people install it and report bugs. I've been using Lucid beta for weeks and I've seen a few bugs. Granted, not as much as with Karmic. LTS releases take their packages from Debian Testing instead of Debian Unstable, which greatly improves quality. Still, I don't think Lucid is ready for production use.
Now, don't get me wrong, I'm all for installing early version to report bugs and help improve the software. I do a lot of work in a Lucid VM. I've reported some bugs on Lucid and commented on the others. But my main machine needs to be stable and I'm not going to take a risk. Not after going through the painful process of downgrading a few months ago.