Long term. I usually play against the Aquilaeians (sp?), Xi'Chung, Rage, Praetorians (sp? again
) and of course the Orks and the Vaxin. The Vikings are also a must. (don't remember if they are tdm or not)
Non-TDM races: the Zorians give a good fight as do the Azaroni (sp? gotta learn to spell
) and the Angelic Regency from UsY. Of course I am also partial to the Star Wars Empire 1 from Kuat Dive Yards but I made the AI
.