i have a full blown sound system in my jeep, radio, 6 speakers, sub, amps. i work for a car audio shop. for a jeep it sounds great. but like said above there is alot of road noise etc
i alway have a amp in my jeep. i do this for several reasons. road noise. when it gets louder you turn up radio to hear it. issue w/ radio power is it can only go so loud before distortion and the road noise will hide it. thats why alot blow the speakers. the amp will let you get to a higher volume w/ keeping the sound clean. i've had the same system in my jeep for over 7y and still sounds great.
1) get nice speakers but NOT high end, dont get low end either. you wont be able to enjoy high-end/high quality anyway w/ road noise etc- probably stick to about $100/pair
2) amp everything..may cost more money but worth it in long run
3) find a decent radio ~$150 should do it. get you into something w/ sub controles mp3, usb etc. ~ USB is GREAT for jeeps or any vehicle that rides rough or off-roads. no skipping
hope that helps some. feel free to ask me anything