I ran a "Little Wilson" 36" magnet mount on my 2nd gen truck. Mounted on the rear edge - wire went straight down and held in place with a couple dabs of Goop. Entered the cab just at the turn of the sheet metal at the bottom through a grommet. Great performance and easy to lay in the bed for parking garages or car washes.
Search Google for cb antenna and you will spend a month reading the results. Several very technical sites pointed to the Wilson and away from the wrapped glass style - I can't for the life of me remember why, but it influenced my decision. Make sure you have someone who knows what he is doing tune the antenna - paid $5 at a local CB shop. As a result of the research, I also had the new radio "tuned" by a local shop for $25 which also got me a printout of the performance. For just "a few dollars more" they can also upgrade a few components for better output.