I have a netbook, and Ubuntu 10.04 expires tomorrow. Should I install the server version of ubuntu 10.04 and install X on top of that? Would what work for support? I love 10.04 only because it runs very smoothly on my netbook. 12.04 and 1304 are very slow on my machine.
Ubuntu announced its 10.04 (Lucid Lynx) release almost 3 years ago, on April 29, 2010. As with the earlier LTS releases, Ubuntu committed to ongoing security and critical fixes for a period of 3 years on the desktop. The support period is now nearing its end and Ubuntu 10.04 Desktop will reach end of life on Thursday, May 9th. At that time, Ubuntu Security Notices will no longer include information or updated packages for Ubuntu 10.04 Desktop. Ubuntu 10.04 Server continues to be supported for another 2 years.
What I understand from this is that only the server edition remains supported. The server does not contain any desktop so the desktop packages will not be supported or any application that runs on a desktop.
In practise I suspect that the repositories will not be moved until the server stops being supported in April 2015 but there will no further updates for bug fixes or security patches.
I would recommend you upgrade to 12.04.
There are several versions of Ubuntu available and while it is true that Ubuntu 12.04 and 12.10 with the Unity desktop are slow on older hardware it is not the only desktop available.
The Gnome Classic desktop is the closest to the desktop as it was in Lucid and instructions on how to install it can be found here.
Xubuntu is LTS and 12.04 is supported till April 2015.
Lubuntu is not LTS: 12.10 is supported till April 2014 and 13.04 till Dec 2013.
You could also consider changing to Lubuntu, which, although will require some adaptation on your part (it runs LXDE and not GNOME as desktop environment), you can customize with your preferred applications and keep up to date.
For example, in my old laptop I work without much problems with LibreOffice, Octave, Gimp, LaTeX, gvSIG, etc.
As @Web-E correctly points out, Ubuntu Server does not have a desktop environment by default, so you would have to install one, which I imagine would lack the support as it would be probably coming from the Ubuntu 10.04 Desktop repositories.