[Culler]

Are your boyz sluggas or shootas?

Other than that, a power klaw for your warboss might not be remiss. You can do without in 500pts but it's really nice for taking out tanks at this point level.

I personally don't like mechanized orks for reasons stated here http://www.heresy-online.net/forums/showthread.php?t=5128&page=2

Basically, they're too easy to kill and too little punch in the trukk. One heavy bolter can easily take out the trukk and/or on average 5 boys in it.

 

[Culler]

For trukkers slugga boyz are a decent idea. I like to use 2 big mobs of 30 shoota boyz for walking though. Shoota boyz are actually one of the best ranged units in the game. The only have a BS of 2 but they have a decently strong assault 2 weapon and still roll most enemy force in CC with their 2 basic attacks per model or 3 on the charge. Shootas in a battlewagon are pretty cool because essentially you've got a battlewagon that can move 12" (13 with red paint) and then fire 34 str 4 shots and 6 str 5 all of which have decent range, which average out to 11.3 str 4 hits and 2 str 5 hits and can usually mean a few dead marines or a lot of dead guardsmen/fire warriors. I actually surprised my opponent today by nearly wiping out a full fire warrior squad at range. Orks make up for accuracy with volume.