This place rocks, you've got some really good responses in here. I will just repeat what the others have said...
Focus on stength gains and use a moderate amount of reps. Usually a rep range of 5 to 8 reps will produce the results you desire if you lift progressively and eat accordingly. You can still gain size with singles and you can still get stronger with high reps, but I've found that somewhere in the middle works best for both goals. Don't seperate strength gains and muscle gains, they both go hand in hand.