Well, since you left yourself open to opinions, here's mine.
1) I only use the LTS versions, as they are more stable.
2) I'll wait at least until 10.04.1 is released before 'upgrading', as this will allow the devs to correct most of the programming errors.
3) I never really upgrade, but rather, do a fresh install. It's less trouble-prone than upgrading.
As for the updates, that's your choice. If you have ultra-fast internet, it won't be much trouble installing them all. On a slower connection, you're going to be in for a really long day. However, I would still give serious consideration to installing the security updates.