I recommend finding a tack shop with a trial polily and RIDE in as many Dressage saddles as you can. Have your trainer help eveluate fit for both you and your horse. The best saddle for you depends on your own conformation and riding style. For me personally, I like a Dressage saddle with very small knee rolls and NO thigh roll, and the seat must be quite shallow and flat. My mom prefers a very deep seat with medium knee rolls and small thigh rolls. I have large strong legs with a long thigh and mom has thin weaker legs with a shorter thigh. She just bought a Bates Innova with the larger knee rolls and REALLY likes it!
Right now, I am actually using an Icelandic saddle. It looks like a Dressage saddle with larger flaps, and a very flat seat (kind of halfway between a cutback saddle seat saddle and a Dressage saddle). I REALLY like it, but it's not the best fit for my horse. So, I'm looking into getting a treeless FreeForm Dressage saddle with their custom "Plus" seat, which is flatter than their standard seat (the seats are removable! How cool is that! Lol). I have a treeless Bob Marshall endurance saddle I use for trail riding that I just LOVE! So I think the FreeForm will be a good fit for Dressage. It looks very traditional with a rider aboard and is legal through all the levels, even International FEI! All of the English models (that aren't funky colored) are legal for Dressge and USEF shows. http://www.actionridertack.com/catal....php?cPath=148