I am, personally, a firm believer in injecting large cuts of meat before I grill or bbq them. Pork, beef, poultry, I've injected all of it before and believe that it has resulted in a juicier, tastier final product. So lets discuss what to do with each.
2 C Water
2 C Apple Cider Vinegar
2 Tbs liquid smoke
6 Tablespoons salt
2 Tablespoons cayenne pepper
2 tablespoons garlic powder
1 Tablespoon black pepper
Combine all, simmer for 3-5 minutes.
I use this for whole hog and pork butts. Its a delicious carolina style injection that I also use to baste the hog with. Butts I usually rub down and then leave them to crisp up real nice like during the cook. You can add a bit more into the butt after you've shredded it down if its a hair dry to moisten it up a bit and add a dash of flavor. I have used this baste on my ribs too. Man do they taste good. I don't foil my ribs at all because they get too mushy that way, and they can if you baste too much. But if your ribs are looking a dash on the Memphis side of crunchy or dry, give em a good mop of this and you'll be good to go.
I very simply inject low sodium beef broth. Add as much to a brisket as it will take. Brisket is such a cantankerous piece of meat that can dry up on you quickly if not cooked just right so as much additional moisture you can give to it is always a good thing. I did some tri-tips not long ago and gave it just a 1/4 cup injection before hand to make sure it was plenty moist and damn did it taste yummy.
I bbq'd a whole turkey last year for a competition. I had plain smoked a turkey before but handn't really tried my hand at a proper bbq style. I checked Amazing Ribs, as that guy is always amazingly spot on with just about all his recipes and he called for a butter injection into the 2 breasts of the bird. This sounded like the most proper way to give that bird SEC Speeeed, so I gave it a shot. Holy crap did it work. The area that most often is dry and withered thanks to it being the thickest part was super juicy and had a great taste to it. This fall I am going to try another one and mix up some good herbs and spices with the butter as well to get a better flavor pallet going on. Another fun tip is to pull the skin back as far as you can with out ripping it off all together and placing Bay Leaves or what ever raw herb you like under the skin, pulling it back over and letting all that cook in during your smoke.