My experience with ubuntu has been the opposite of yours. I've found
8.04 LTS to be rock solid.

As for stability, 10.04 LTS should be just as good, if not better.
Canonical has recently made a change in that regard. Ubuntu used to be
based on debian-unstable, but beginning with 10.04 it is based on
debian-testing. I'm running 10.04 Alpha on 2 machines and while I've
seen a few minor buglets here and there, it's totally usable. I'm
looking forward to updating all my 8.04 machines to 10.04.

Of course, they also offer the fedora-style 6 month releases for the
adventurous, and I try those on desktop/laptop machines, but my servers
are all on 8.04 LTS and won't be upgraded until after 10.04 is released,
if even then.