Normally, it should be possible by just keeping your database and replace all the other files. But you will lose all your installed Mods (except these, which have been implemented in V 3.4)
exactly which Mods come pre-installed? I'll need to know so that I can re-install them all once v3.4 is released (prior to replacing the current live site)
Just becareful I left for a while and just came back and I downloaded a couple of mods for 3.3.05 the said it would work and come to find out they have Language Packs in them and I thought the Language packs were for 4.X. I have no use for Language Packs so I'll continue to rip them out.
I believe Davio was working on a new version of the Poll MOD (he's on vacation now), and if I'm not mistaken Nathan is planning on finishing the Active Users MOD for 3.4. Both might take a little while before they're released though.