Something simple so its not too expensive because then he will think that he has to give you something expensive too, and then he will feel bad so I wouldn't recommend that! You could give him something that guys in general like, or what would be a really good gift would be something that he needs or something he has wanted for a long time, or something that is special between you and him.
A good 19th birthday present for your 2-year boyfriend would be a fancy smartphone.
a werewolf girlfriend or boyfriend
depends if they like you.
make somthing
smile by uncle cracker.
It depends on the kid.
tickets to his favorite band/sport team
A card or a day out with each other.
you don't have to give him anything, but he would like it if you did but I don't know your boyfriend so I don't know what he likes.
If that's the type of things he likes.
To figure out what a good Valentine Day's gift for your boyfriend, you need to know what he is into. If he is into his appearance you can buy him something to wear. If your boyfriend is into music or movies you can get him a CD of his favorite artist or favorite movie. You can always just ask too.
This really depends on what your boy friend likes. Get him what HE likes.