Bike racks and carriers all come down to preference. Since you have a hitch, there are plenty of options going that route, and you can choose from a carrier that can fit up to 4 bikes depending on your needs. You could also choose a bike carrier that mounts to the spare tire, this is probably your cheapest option. Finally you could get a top mounted bike rack since you have a hard top, the only problem would be if you wanted to take the front panels off or not. Each option has drawbacks. For instance you can't pull into a garage with a bike on top of your jeep, but you could if you have the hitch mount. Hitch mounts scare me sometimes because if you're rear-ended not only is your jeep damaged, but also your bike. The kind of bike you have also may play into your decision. If you have an expensive bike that costs more than your hardtop like I do, then you're gonna want an option that is locked. In my opinion, Thule and Yakima make great products. I tend to lean towards the Thule side because I can get great deals on them through my local bike shop. Here are two sites that might help you out.
Jeep Wrangler Bike Racks & Carriers - JCWhitney