I can't stress this enough. RJJ was awesome, but if you fight like him, you'll get murdered. You ain't as quick as Floyd, don't hit as hard as Pac, and you don't have the chin, handspeed, or ring smarts of the legend Ali - so don't fight like them.
But...that being said, fight like the best conventional fighter you can find, and in my opinion, in this day and age, that's Juan Manuel Marquez.
Watch this fight with Juan Diaz - this, to me, is Marquez at his absolute finest. His physical gifts have diminished a bit with age but he's still so fucking smart that he deals with Diaz's charge early on, and slowly, methodically breaks him down with the straight right hand the lead uppercut.
Also, watch his pivots- he truly has some of the nicest moves in the game; he gets in trouble, backs against the ropes, and bang, he's out and he's punching.
Another terrific fight is his fight against Katsidis, where he does much the same thing - take on the early charge and then methodically destroy a younger opponent.