radio/stereo/amp/new tunes box

Wow - I took my 68 B'cuda dash apart today and removed the old am/fm cassette player radio/stereo. I thought - well, that won't be going back in. I came upstairs and got on eBay looking at new tunes boxes. I just bought an mp3 player recently and love it. So I thought - well, get a unit that I can plug the mp3 player into and I'll be set! Wow - What a selection. Again - It's like taking a sip from a fire hydrant!
Looks like I can get a nice looking unit for around 25-50 bucks. Then I looked at amps. 1000 watts !!?? Oh, well that's only 19 watts x 2 RMS. I thought - Why do these amps have all these knobs? I thought you hid the box somewhere, plugged some wires in and ran some wires to the speakers.
It's been a long time since I bought stereo equipment. I don't need much. I don't want to drive down the road going thump, thump, thump! I just want to hear some Clapton or Allman Brothers or Stones or such.

What is everybody else installing in their Vintage rides other than the original units?