JDM wrote:
The only nervousness that I've had about it is that testing isn't officially security supported so sometimes security updates have been made available later than they were for stable.
Actually, that hasn't been true for a couple of years. These sources work fine and are updated frequently:
deb
http://security.debian.org/ lenny/updates main contrib non-free
deb-src
http://security.debian.org/ lenny/updates main contrib non-free
Just to add another vote, I've been running lenny without issue for a while now, and it's been extremely stable. Most of the changes from etch are incremental (other than new versions of packages), but the overall feel is much more polished. Also, not to rag on Ubuntu, but most of their "features" such as dash, etc. are just pulled from Debian testing/unstable.
On my Linode account, I took advantage of the fact that you can resize / clone disk images. I resized my disk down to < 1/2 of my available storage, cloned it, and did the upgrade. That way, if something went horribly wrong, I was a reboot away from having Etch back (nothing did, btw).