brancher, there are many posts here in the cruiser forum devoted to this exact topic. Just do a search on yoru deisred keywords and I guarantee you'll get all kinds of information.
I myself started such a thread about a month ago when I was researching aftermarket pipes for my Vulcan. Most of the folks in here are partial to Hard Krome and Vance & Hines. But you'll find some Cobra and Jardine fans too. It all depends on what your goals are, how much noise you want, what your budget is, and what is available.
Good luck, and happy hunting!
