Personally, my top favs are: (not in ranking, random order) -Ant Buster -Desktop Defense -Doeo -and that one TD i cannot remember the name of but it's easily distinguishable by two things; Uber Man and the Chuck Lee 'Tower'!
but, I like most games so, THERE ARE NO FAVORITES =)
I rele like autumn war the zombie game. Some people dont like it because they think it's too tactical bu those are the kinda games i like. I also like the field commander series al ot too altho the 3rd one is the best.