not looking to add a sub, but wanting to put the best (and by best i mean the cleanest, crisp sounding) components and rear speakers in the truck. I'll change out the head unit and add an amp to run all 4 speakers. Now. . . . what should i get???

 

Oi, your going to be getting a lot of opinions in this thread. I recommend you go down to a Car tunes or Best buy or somewhere where you can test a variety of speakers, and test them all.
I use Sony's all the way around with a stock headunit. I used to have an aftermarket radio and sub and what not, but about 3 months ago, when i was dead set on selling my truck, i sold that stuff to a buddy, but kept the speakers. I didn't end up selling my truck (obliviously)
Anyways. Sony's (not those gay Xplod ones), They've got a decent low end, they peak out about about 15k Hz (you can't really hear all that much farther into that range anyways.) and the mid range has a decent sound, not really boxy or cheap.

 

I am not an audiophile but I like the Pioneer Speakers.
Always have and may always but they sound good to me; not the high end stuff the D-Series.

Luck on your choices, like StxDangerRanger said, go to a store and listen to some and see if they respond to your music the way you like.
Take a CD or the Cable to attach your iPod or other Music Device, I think the iPod will probaby give you the best sound to determine if the speakers will work for you.