Lots of good suggestions so far but there is only one thing I know of that doesn't fail but it's a bit extreme.

I've spent months on end in a tent. After the first couple of weeks of being miserable my body adjusted and I slept like a babe on an ultra-light thermorest (about 1" thick). A couple of weeks after that and I was OK on hard ground so long as the ground wasn't horribly cold. I still tended to use the pad.

So i guess it depends on where you want the trade off. A few nights on your pad at home before you go camping may cost you a bit of sleep at that time but will go a long way towards getting you some quality down time on the trail.

Alcohol. Lots of it.

You'll sleep like a log.

Assuming money is no object, how about something like this lightweight collapsible cot?

http://www.cabelas.com/p-0054765518236a.shtml

This might be totally obvious, but just in case, those thermarests are not really "self-inflating" - they unroll on their own, but you can blow more air into them.

Like I said, this probably goes without saying, but I suddenly imagined you out there sleeping on a half-inflated mattress, so I thought I'd mention it.

This answer relates to backpacking where a lightweight sleep system is preferred.

Various companies make light (i.e. comparable to a thermarest) inflatable mattresses which would be an improvement over a typical thermarest or any closed-cell foam pad (Big Agnes Inflatable, Therm-a-Rest NeoAir).

A pillow can really help too, particularly if you sleep on your side. Inflatable pillows are available these days (Montbell), although I usually just put my puffy jacket in a stuff sac and use that (if it's not so cold that I need to wear it).

I always take a full-blown (harhar) air mattress car camping, but it may not be feasible for backpacking.

How about some kind of cot? They can be pretty light and compact, will get you up off the ground like a hammock, but will probably provide more support.

In case you decide to try hammocks, I have one of these:

http://www.eaglesnestoutfittersinc.com/

They are amazing. Comfortable, adjustable, holds 400 lbs. and packs down to the size of a grapefruit. I have the onelink system, which includes the hammock, bug net, and rainfly. They have tons of other great gear for campers who like to pack light.

Fantastic customer service, as well. My first hammock kinda died due to a possible combination of cows, a dog, and a strong thunderstorm. I bought another one, since I figured it was my fault for not remembering to bring it inside before the storm hit. A few weeks later, I realized they gave me the wrong rain fly, and I called customer service. Out of curiosity, I asked if I could have had my hammock replaced instead of buying a new one. The guy said since I already paid for it, he'd ship me out the correct rain fly, and I could keep the wrong one, which costs more than the hammock anyway!

Personally, I think they're a great alternative to the tent/cot combo.

Benzodiazepines! Just don't take too much. All those little bumps and noises disappear.

So, I can't make any recommendations for backpacking, but I CAN make some recommendations for car camping. I have an older friend (taller woman in her 60s) who swears by the following combo:

- Cot (she has the Coleman one, and says it works great)
- 2- or 3-inch thick foam pads which cover the whole of the cot.
- Put a thermarest on the top layer, if absolutely necessary.

I know other people who swear by a thermarest that has a top layer of down -- the additional warmth around the hips make sleeping much easier.

One other thought -- what about a couple of pillows that you can shape into a donut, and then slip it under your hip?

Extra cushioning with clothes to pad those bony spots always worked for me-but hey-I usually camp in a pickup bed.

At first I thought the inflatable sleeping pad (I had a top of the line Thermarest) seemed like the most logical solution, but after years of camping discomfort as my hip bone rubbed the ground by bottoming out on the pad, I switched to an old school 2” roll-up foam pad, which was an improvement, but bulky and still uncomfortable for my hips.

Recently I bought one of these egg crate pads as a supplement, to go under the foam, and I was delighted that it solved my hip discomfort. A recent camping trip with space limitations forced me to choose between the roll-up foam and the egg crate, and since it was a short trip and the egg crate was smaller, I tried it with the egg crate alone, and to my amazement, it was just fine all by itself, my hips didn’t grind the ground and I got a great night’s sleep.

The egg crate felt much harder at first than the inflatable, but it is actually more supportive over the course of the night, and it will never leak, which is a problem with all inflatables eventually.

Costco sells these foldable pad/mattress things for about 45 bucks that are great for car camping. I slept on one for about a month last summer and slept great. They're much more comfortable than an air mattress.

They're not listed on their website for some strange Costco-ey reason, but are similar to this: http://www.amazon.com/Adult-Trifold-Hide-Folding-Mattress/dp/B000F4EJO4/ref=cm_cr_pr_pb_t

Oh, just to add a backpacking suggestion, I'll mention that the thermarest-type pads aren't actually particularly good in terms of cushioning-- insulation is the reason why you buy one. It might be worth throwing a trusty old blue foam pad (or similar cheap camping pad) under the thermarest to see if that helps.

Coleman makes a variety of inflatable air mattresses. They also make compressors that plug into car lighters or that have rechargeable batteries. All of this stuff is relatively inexpensive and available at Fred Meyer.

However, this definitely isn't light gear, so it's not feasible for backpacking. Is it possible to sleep on your back if you bend your knees? Just rolling up a jacket under your knees would keep you in position and take tension off of your lower back. That works pretty well for me.

Also, have you actually tried a hammock? You should try one in town and see how it feels before ruling it out as an option for camping.