You don't have to use 5x7s, btw. You can buy a 6.5" component set and it will fit just fine. Some of them come with adapter plates/baffles, but if they don't, you can make some very easily. I would recommend a round speaker over a 5x7 for sound quality, although in theory you can get a little more midbass out of the larger oval speaker.
I ran JL TR 5x7 coaxials for a while. Not bad. They get loud. Then I upgraded to JL XRs. They sounded a little better, were mounted coaxially, but came with external passive crossovers. Then I moved those to the rear doors and put Boston Pro 60s up front, running active. They absolutely ROCK. With a decent (new) amp, they will probably be out of your price range, but they are very hard to beat at their price level. They like a ton of power, so that will drive up the price of your amp, too.
Everyone likes a different sound. And speakers sound different in different vehicles and on a wall in a sound room. Good luck.
