In reply to GravitySucks:
I went through the whole rigmarole of getting a new saddle this time last year. I tried (and spent money on) several different ones before finding a solution.
The first thing you must realise is that everybody's bum is different and thus every recommendation you receive on this thread and elsewhere may not apply to you. I learned this the hard (and very, very painful) way.
The second thing you do is go to a decent bike shop and get your sit bones measured, they do it with a very simple memory-gel thingybob which you sit on. You can bodge it at home but the results I got at home were different to the undoubtedly more accurate results with the profesional gel thingybob.
The bike shop should then recommend you a saddle, even offer to order you one in if they don't have it in stock. You may be able to buy your chosen saddle cheaper online but then your bike shop will go bust and won't offer the saddle-measuring service; go figure.
The third thing you do, if you haven't already, is invest in a proper bike fitting. I used to be snooty about bike-fitting but I was getting all sorts of aches and pains (riding 100-200km per week) so I bit the bullet and did it (with my properly sized new saddle). The results completely changed the geometry of my setup, and since then I have ridden several thousand km without a single squeek of pain, it's magic.
Good luck!