I would put terries on the top of the list. You can normally get 3 terries into b2b (except against elven bolt-throwers), which is far more effective then JSoDs and FSoDs. The only problem is that there increased killing ability also means that they might be better used attacking missile troops.
One of my Favourite tactics is to put the Nike Saurus in a unit of skinks. in the first turn you can move 12 " toward the warmachine and in the second turn the saurus can charge out of the unit and Boom Bye bye Mister Boltthrower. In the best case you overrun and have a str 7 beast behind your enemy lines., ready for a charge in the back of something. Terradons are also a good choice, but be careful if the Warmachine is set up near another unit. You don't want a combat with multiple foes. Other than that if your enemy has lots of war machines you might consider to try to get the lore of metal spell that disables them. Oh yes and Salamanders, of course. If there is nothing better to shot at, 3 salamanders can whip a machine crew really bad. the (hopefully) sheer number of hits should do well, at least against elven bolt throwers witth their 2 crewmen. but on the other hand, if you are playing against pointy-ears than there is almost always a better target.