After denting my TJ's oil pan and scratching up the transmission while playing in the rock garden at SideRoad Jeep Supply, I decided it would be wise to invest in a nice, heavy duty engine skid plate. The best option for the 2.4 i4 TJ is the SkidRow 4x4 skid plate. It went on fairly smooth, but since my center skid front lip was all bent out of shape, it took a little motivation to get it into place. Overall I'm extremely happy with the quality of the skid plate, and would buy it again; although I don't think I'll need to, this thing is BEEFY!
I also put a nice ding in the side of my tub after coming off the ledges at Tuttle Creek a few months back. I decided some rock sliders would be the next purchase, too. I ordered a set from Quadratec, and while I would have loved to buy some from PSC or MetalCloak, or another reputable company, these were in my price range and would do the job. The install was easy, after I got over drilling 16 holes in my frame. :)
Another purchase I made, was the Smittybilt G.E.A.R. tailgate organizer. It's a relatively easy product to install, and is a great storage solution for stuff you need on the trails quickly. In the smaller bag, I store my ARB air compressor accessories, and in the big bag I keep my straps, tree saver, air hose, EZ deflator, etc. I added an American Outlaw tailgate stopper to keep the tailgate from slamming into me while parked on a hill. Two cheap, but great accessories to add to a TJ.
The last, and probably most important accessory I've added lately, is my ARB single compressor. I mounted it under the hood and while this isn't the most ideal spot, I didn't want it taking up any space inside. The TJ is already extremely small, and on long camping trips I didn't want to be limited to what I can bring more than I already am.
Air up times are quick, for what it is. I can air up from 15psi to 35psi (all four tires) in less than 10 minutes. Obviously a normal compressor will do it much faster, but there aren't normal compressors at every trail head. Airing up is as easy as opening the hood, flipping a switch, plugging in my air hose, and we are ready to go. Eventually I may add a small air tank, which will give me the ability to run small air tools if needed. Right now, I don't find that's necessary.