I moved from 12.04 64bit to 12.1064bit on my desktop machine and run 12.04Lts on my servers.
From a technical aspect?.. I don't have enough reliable technical knowledge to offer any advice that would be constructive.
From a usability perspective. 12.10 seems smoother and a little sharper. It's video is more polished. On my 64bit 3.0ghz 8gb ram Dell 780 desktop it's beautifully smooth.
The 12.04 seemed a little more stable, with the qualifier that I play a little and have destroyed more installs than I can remember :)
I'm using Unity at home and xcfe at work after going through KDE, LXDE (this is worth having a look at with lower than 4gb ram machines) and Gnome.
You can install gnome desktop on any of the Ubuntu flavours, but a direct download and install is more convenient and a little tighter integrated. KUbuntu(kde), XUbuntu(Xfce) LUbuntu(Lxde).
Can I suggest you download a few and make some bootable cd's, give 'em a whirl and see what you think? If your still unsure you can install different desktop environments through out the different Ubuntu flavours.
I've warmed to Unity, but as it turns out with customisations all over the place, it now looks and behaves more like a mac (after spending 20 years on windows), go figure! :)
Always remember, Linux can't be judged as an "operating system" in the same vane windows is. It's actually a usability experience. You can do what ever your imagination can conjure, including customising the environment you work to an unrecognisable point.
Linux enables you to run a $50 Rasberry Pi as a home media server, or run a Particle Accelerator buried under Switzerland and go hunting for Higgs particles :) I'd be guessing you and I somewhere between :) Which gives us enormous choice.
Quick tip! Run at least 2 partitions! one as a home partition and one for boot.
After trashing so many installs (Entirely my fault, nothing to do with Ubuntu or Linux. I poke screw drivers into light sockets :) ) Having your /home directory on a separate partition is a god send! :) And do backups! Damn it!