Pontian and armenian heavy infantry compared to legionnaries come to mind.^^ or siege engines.

Shipri Tukul are also one of my favorites, although i often hae the feeling that they are too expensive for their preformance. still they are an essencial part of my parthian royal army(infantry devision) useing them as line infantry is my way of getting rid of my surplus money as I don't like to use elephants (not to mention getting them from india to syria) and find that a navy of "boats" is just not ipressive enough for it's price :D still i think they really could use 1-2 extra armor points for their clothing or so.