I like the sound of the Polk DB691 in front and the Polk DB651s in the back doors that I installed, though they sound even better with an extra amplifier mounted under the passenger seat. Depending on the amp, the extra amp might mean putting a line output converter in the dash that converts the speaker level output from your oem headunit to RCA outputs for the amp, though MANY amps now can utilize high level speaker inputs.
If you do not mind paying a little extra for great customer service, free shipping, unlimited tech support AND a 60 day return policy, Crutchfield.com is the place to shop for your speakers...their sales reps are fantastic at listening to your needs/wants and they have immdeiate access to a proprietary tech base that lets them tell you what will and will not fit in your truck.