I look for updates every day on 10.04, and let it install whatever
updates there are. I've never seen a problem on any of my 10.04 systems.
It's possible that yours is an odd corner case, maybe unusual hardware
or something, but I'm betting it's not the updates but something else
that happened.

If you have a low spec system, lxde will be much snappier than gnome.
You can run lxde on ubuntu as well. Mint is just a repackaged ubuntu
after all. I like what I've seen of mint, but it's just as easy for me
to install "ubuntu restricted extras", tweak my wallpaper and themes,
and I'm all done.