The M8100 is the British mil version of EF95 and is the same tube as CV4010, you will sometimes see the same tube co-branded as M8100/CV4010. Some tubes to look forward to are the more popular American 6AK5 variants. Some of the best are the US Army 6AK5 (US mil-spec tubes in general are usually very good), RCA Command (the Command line is RCA's premium consumer brand), GE Five Star (five star line is GE's premium brand), Sylvania Gold Brand (the Gold Brand are mil-spec tubes, there are a lot of rebaged GB's, however, so you want to make sure the tubes you buy have golden legs), Amperex made some 6AK5W (the W is for Improved, go figure) that were well received as well. There are quite a few other manufacturers of 6AK5 as it's a relatively popular tube back in the day.
The Western Electric version of the 6AK5 is called the 403A. There is an improved version called the 403B that was manufactured by a few companies besides WE as well.
The communist-block version of the 6AK5 is 6J1P, 6J1P-EV is the improved version.
Some of the other 6AK5 equivalents that I know of that are not listed in the ebay ad are CV850, DP61, PM05. There might be others. 
EDIT: Here's a link to the Yen Audio Store's little dot upgrade tubes page, a lot of head-fiers have PM'd me for this info so here it is!
Edited by Dept_of_Alchemy - 6/29/11 at 6:13pm