<Waves to her guildie! Heya MJamesS!>
Dulfy's done amazing work. Her numbers are somewhat outdated now.
Here is the list of the population of EU servers.
I did a bunch of math at it, and found someone who had a handle on how many people are on a "light" server and so on, and calculated the likely population size of the servers:
Theoretical 24 hr average population over the last two weeks.
Details on the math here: Population Estimates for the Top 20 US Servers (I know it says US not EU, but the math is the same).
Here are the top EUR-English servers as of yesterday. Holler if you want the French and German ones also...
Tomb of Freedon Nadd (PvP EUR English) Population ≈ 1424
The Red Eclipse (PvE EUR English) Population ≈ 940
Nightmare Lands (PvE EUR English) Population ≈ 640
Dune Bantha (PvE EUR English) Population ≈ 600