I would second Tokyojoe's motion to go with a high quality whip antenna like Wilson, Maxrad, Sinclair etc. These antennas have base coils, so in addition to giving the best range, they'll help block noise from getting into the CB, and CB noise from getting into your AM/FM. IMO, they're also alot more durable than the fiberglass ones, where the wire tends to break where the fiberglass meets the mount.
As far as I know these antennas only come with the NMO mount. This is the were the antenna screws onto and is the mount you will find on 99% of professional 2-way VHF, UHF and cellular antennas. The advantage of this is, once you have the mount, you can easily swap your antenna for, say, a cellular antenna and plug it into your cell phone (you'll need an adapter at the phone side).
You can also cheat and get an NMO mag mount until you're brave enough make things permanant

(I have trouble getting this brave).
