Infinity is nice, alpine's new type-x are nice.
A guy that is know all around town for doing car installs, put in some new Diamond Audio and said they are the best speakers he has ever heard.
Same guy puts waterfalls and fish tanks in peoples cars.
Ive used Infinity Kappa speakers, and Kappa Perfect subs.
I'm probably putting in Diamond audio speakers and 4ch amp in, when ever i get around to it, no sub this time.