My experience is similar to Richard's: I've tried a lot of different medications and I don't do my exercises either.
I was diagnosed in December 1997, after complaining of various back and hip pains for a good half a year and averaging five hours of sleep a night. I was 25.
Since then I've mostly been on high doses of naproxen: 1,000 mg/day, increased to 1,500 mg/day during flares at my discretion. I've experimented with other NSAIDs, with poor results: celecoxib (Celebrex) was far too weak for my case; indomethacin did funny things to my head; diclofenac (Arthrotec) did funny things to my liver (I was prescribed double the adult dose, and took sulfasalazine at the same time). Naproxen -- crude, powerful naproxen -- has given me the best results with the fewest side effects.
You can just imagine the effect on my stomach lining. Right now I'm taking Pantoloc for the stomach; I've used misoprostol and famotidine prior to this, but Pantoloc works better than that.
I had a stiff neck early on but it's mostly resolved itself since (those neck exercises are easy to do at your desk, by the way -- they were the only ones I ever did with any regularity). Otherwise I'm in the same boat as Richard: sedentary Ottawa-area government and tech work is inimical to a happy spondylitic spine. We should be forest rangers or something -- actually, I'm serious: in September 1998 I hiked over 65 km in Banff National Park and had no pain afterward for three weeks.
My inflammation seems to be focused primarily on the sacroiliac joint and lower spine, with secondary effects on the rib cage, ankles, elbows and wrists during severe flares. Overall flexibility and mobility is very good, considering, but I'm in at least some discomfort every day.
I've noticed that flares occur during periods of extreme stress, and I'm looking into that. I've always been a stressed-out individual, even as far back as junior high school. Stressful incidents tend to exacerbate it. Family and domestic conflicts are killer. At work, the problem isn't so much so-called "high stress" deadline-driven periods of panic -- those I can handle comparatively well. But not hostile work environments, unfriendly co-workers, or unresolvable unpleasantnesses. Travel isn't good either: I stress out just before departure and usually wake up with profound back pain during the trip.
Right now I'm in a doozy of a flare. I was away over the weekend and am in the midst of conflict with various friends and family members, so this is no real surprise. Cause and effect. More pills, please.