I use Natural Factors RxOmega-3 Factors Pharm grade (fish oils with very high EPA/DHA concentrations), Osteo Bi-Flex Advanced Triple Strength, Forged Joint Repair, and Skeletal Balm.
Skeletal Balm is by far the best thing ever. That stuff just works so well to help me have pain free workouts. I rub the balm on pre workout and wrap my elbows, or use neoprene sleeves on my knees. When I get in the gym I warmup for a few minutes on the bike to get the heart pumpin, then rotate my joints (shoulders, elbows, wrists) at least 20 times in each direction, and make sure I do enough (but not too much) warmup sets.
I find all of this, and keeping my nutrition and hydration up to par with my workout demands helped reduce my injuries immensely.
Now I get hurt only when doing things like playing with my son in one of those bouncy castle things, lol!