if you don't want to spend too much (eg=old games) and looking for rts', there is the myth serie...
3d environment, nice plot(fantasy), no collecting resources/building stuff, just military strategy, and a lot of em
i played at the first two, loving em, there is a third one, full 3d like warcraft3, when in the first two the units where 2d sprites,
the big problem of the first one was the bad ia, enhanced a lot in the second one
of the same genre there are also ground control, full 3d, nice but little annoying in my opinion, shogun: total war, very very nice as i've heard but not full 3d, and a Dune game (the title was emperor: battle for dune or something like that) that i don't know about
enjoy:)