goblins can be very useful but I only ever use them to either A: attract cannon fodder so I have them running around keeping cannons busy or B: use them against the best enemy units to tie them up, then use my boyz to flank around the back 
also the arachnid is a great unit as well usually steam rolls infantry
The fanatics are a good unit also!

also the arachnid is a great unit as well usually steam rolls infantry
The fanatics are a good unit also!