Cobra 75-WX-ST CB - Putting a 2-way radio in a TJ can be a challenge. There aren't too many locations to place it. The Cobra 75-WX-ST Citizens Band radio is very space saving, and a good CB. Only a small box needs to be installed in a hidden area. All of the CB electronics are in the microphone, which is just a little thicker than a normal mic.
I install the box hidden inside the front of my center console, under the airbag cutoff lock. From there, the microphone comes out in front of the transfer case shifter and is mounted next to the steering wheel. This arrangement takes very little dashboard space, and allows me to remove the CB as needed.
www.cobraelec.com 

External CB Speaker - I found the speaker built-in to the microphone on the Cobra CB was okay when sitting still, but while driving, it was hard to understand others. I purchased a small 4" external CB speaker from Radio Shack. Using a couple hose clamps, I mounted the speaker at the center of the rollbar. The wire is hidden under the rollbar cover and the carpeting. The Cobra 75-WX-ST CB includes a plug for an external speaker. This makes it a lot easier to understand others on the radio.

Firestik CB Antenna - I installed a 4' Firestik CB antenna in the rear, passenger side. At first, I had it mounted behind the spare tire, but there wasn't any room for the antenna to flex. Moving it away from the tire allows the antenna to flex and swing on it's spring when hit by low trees. I choose the 4' antenna, as I didn't want it sticking too high above the top[ of the Jeep. I know transmission and reception are probably lower, but it's more out of the way. Almost all of my use for the CB is on the trail among other vehicles. I also like the weather channels this CB receives. It helps to know what the forecast is for the area BEFORE I head onto the trail. I found the antenna mount at a local electronics store. It looks like it came from the factory.
www.firestik.com

Garmin GPS V - I was looking for a way to keep a record of where trails were located at. The Garmin GPS V is a nice, compact GPS. It allows ,me to store 20 reversible routes with 30 waypoints per route, and 1900 points in a track, with 500 independent waypoints. It also accepts Topo maps to be loaded directly into it, up to 19MB. It acquires the satellite signals very quickly and has numerous screen options. With the recent lifting of government restrictions on GPS position accuracy, I now know my exact location to ±14'. 
I also purchased Garmin's Topo Mapsource software. This allows the topographical maps to be loaded directly into the GPS, and onto a PC. If loading the maps onto the GPS isn't important to you, the shareware software OziExplorer is an excellent utility. You can bring in your own digitized topo maps into OziExplorer and download/upload information directly to the GPS. This is a good way to exchange GPS information with other users, regardless of the brand of GPS they use.
The antenna attached to the GPS works very well. Even inside my Jeep with the hard top on, I have no problems acquiring signal's from 10 - 12 satellites. I was going to use an external GPS antenna, but this one works perfectly fine. Knowing where you are on the trail and which to get out has come in handy. It's easy to loose you're bearings while exploring new trails. I especially like the setting tracks. They become my "electronic bread crumbs" and are filed as a record of the trail for future reference.
www.garmin.com

Customized Light Switches - I read instructions on how to create a customized panel for up to 6 factory switches. By replacing the ash tray in the dash board with another 3-switch bezel, you can have a factory looking location for 6 factory switches. I already was using 2 spaces for the rear window defogger and rear window wiper, so I had room to add 4 factory switches. These are factory fog light switches that were used on the '95 - '99 Wrangler's, before the fog lights control was on the same controls as the headlights. These switches illuminate when the dash lights are on, and include an indicator light when they are turned on. The space below the second bezel is for a second cigarette lighter. I decided to further customize my bezel, making room for three more toggle switches. These additional three switches won't be factory switches. Instead of toggle switches, I can install the ARB switches here. The end job is a nice, clean looking custom setup for various switches. I used on of the new switches to control the on-board electric air, and the others will be used for various driving and rock lights. Although real nice looking, factory parts are not cheap. The bezel and 4 light switches came to $125.

Fuse Block - Adding lights, radios, GPS, and other electronics makes wiring and fuses a mess. I installed a Painless Wiring auxiliary 7-fuse block under the dash on the drivers side. This provides 3 unswitched and 4 switched circuits. Each with it's own 20amp fuse.
www.painlesswiring.com

Grounding Block - I also added a common ground block, which provided 6 grounded terminals. This makes it easier to ground additional lights without looking for aplace to ground them. This was installed on the firewall, under the hood.