Uniden or Cobra's higher end units are worthwhile. Although modifying 10-meter ham radios will give you more power, and the audio quality is often times better than "export" CB radios. I use an Icom two-way radio that I modified for covering the CB band (simple as cutting a diode on the circuit board)...the antenna is a 102" full-size whip off the rear quarterpanel. Depending on terrain, I get about 15-20 miles.
The antenna is really the key. Get the biggest **** one you can fit, and mount it on a metal part of the vehicle. Drilling a hole is the best way to mount an antenna, I've never been a fan of "mag-mount" antennas, especially for CB. Not only do they scratch the paint and collect moisture, but they don't provide a good RF ground at CB frequencies.