You'll get an excellent result and exactly what you're looking for (ie: hours of playing in comfort) from a
mapex - even mid-range - suede or faux suede saddle-style throne, providing you don't insist on having a back rest. I personally have never needed one. A posture correction will do so much more good to your back than a back rest will.
I paid around £90 for mine, so it wasn't bank-breaking, but I've had hours and hours of enjoyment from it. It's never let me down.
Roc'n'soc are also awesome, don't get me wrong, but I agree with Slingerland, it really does depend on what's good for you. Go into a shop where you can try one out if you can, and when you buy, keep the receipt just in case.
Hope this helps.
Keep drumming.
DrTazzle (aka: DrMapex)