Hey, pleasure to be here. I'm trying to get back into the game after several years away (I was a kid when I originally bought this stuff, and never actually got a chance to use any of it), and though that I might ask you gents for guidance. What I have at the moment is as follows:

Cave Troll w/Spear x1
Goblin w/Spear x15
Goblin w/Bow x16
Goblin w/Shield & CCW x6
Orc w/Bow x3
Orc w/Shield & CCW x3
Uruk-Hai w/Shield x3

I'm not sure how viable a force this is, and what might be some good additions to it. Any advice?

Well technically goblins and orcs are not mixed in the same force. Bu you could use the orcs has stand-ins for goblin prowlers or something.

Looks like a start for a Moria force. You'll need a hero to lead them, and Durburz is a good one. Adding a shaman, a couple of blisters of prowlers, and maybe some bats could form a decent 500 point army. You might find the Khazad-dum sourcebook useful. Also, some new goblin models have recently been released, you'll find their profiles in the November 2010 issue of White Dwarf.

Hope that helps...