Of all the people that responded here (some really good advice, too), only Happy_Hamer and I have owned or do own Jeep TJ's. I currently use one as a daily driver (when I'm not riding the motorcycle). Most of the radios that have been recommended will NOT fit on the dash of the jeep. I personally have run a couple different radios in the heep.
The Magnum 257 fits nicely and is a pretty "loud" radio on AM. On SSB, it can be nice and clean, as long as you couple it with a noise cancelling mic like an Astatic Road Devil. I have talked on 10 meters with it and other guys have asked me if I was using a Kenwood. Keep in mind that the jeep is a noisy vehicle. The problem with the 257 is that the IF stage of the radio is just way to wide open. The RX picks up everything not related to RF. Jeeps are very susceptible to ignition, alternartor, and fuel pump noise, and you hear it all through a 257.
The Midland 79-290 is the radio I currently run. The RX is not near as wide open as the 257, and thus it doesn't pick up all the trash. The stock mic is garbage. The radio still picks up some ignition noise (I've tried everything to filter it out), but overall the RX isn't bad. With a decent tune up from Justin, I get 30 watts out of the radio. Personally, I don't think it's all that bad of a radio for what it is. The best part about it is that it's a dual final radio, so when you smack your antenna while off-roading, it's unlikely you'll pop a final in the radio.
Lastly, I do quite a fair amount of off-roading in my jeep in the mountains and desert. I have a similar mount as yours that I fabb'ed that is real strong. If you use your jeep as a daily driver, I suggest two antennas: a bigger one for the road, and a short one for off road. The short one is for trail communication and so it doesn't smack everything. BTW, there is room for an amplifier. I can show you how to fit one very neat and nice
BTW, something to consider if you're a serious off-roader: Get your general ham license and get a good ham rig like an Icom 706. If you ever get stranded or twist off an axle, you'll be glad you have the ability to communicate around to all the repeaters on hill-tops and on the HF bands to other stations around the country. Just something to think about.
My Jeep:
'99 TJ Sahara w/ dana 44 rear end
33" BFG MT's with 15x8 American Racing wheels
4.5" Rubicon Express Superflex lift with Adjustable upper and lower control arms.
Rubicon Front and Rear adjustable Track Bars
JKS Front Sway Bar disconnects
Currie Enterprises Slip Yoke Eliminator
Currie Enterprises Rear Drive Shaft
TeraLow 4:1 Transfer Case Conversion
Superior Axle & Gear 30 spline front Dana 30 axle conversion
Superior Axle & Gear Chromoly Super Dana 30 front axle
Superior Axle & Gear 4:10 front and rear gears
ARB Air lockers front and rear
QuickAir2 Air compressor w/ Sun Enterprises 2 gallon Air tank
Skid Row engine skid plate
Jeeperman rear bumper, spare tire carrier and jerry can holder
Kilby Enterprises Gas Tank skid
All J Products Boulder Bars
Ramsey 8000 ProPlus winch
Hi-Lift Jack
Midland 79-290 CB
Custom 2x2879 linear amplifier
Firestik II 4' CB antenna with custom antenna mount
Icom 706 MKIIg transceiver
Comet 2/440 mobile antenna on custom antenna mount
Hi-Q 4/80RT 6m-80m antenna
Lots of recovery gear (I hate getting stuck!!)
Lots of sweat and blood setting this whole thing up!!!