There are a few different classifications for English saddles, here are the basics:
- All Purpose: have a semi-forward flap, relatively deep seat, rounded cantle, and put you in a neutral position. You can do mostly all basic English disciplines on this saddle, it's good for basic jumping and dressage.
- Close Contact: has a forward flap, usually has knee and/or calf rolls (to help secure the leg), and a forward, shallow seat. It usually has a square back cantle. Used for jumping. You can do basic flatwork in it, but it's not designed with dressage in mind.
Dressage: very straight flaps, usually has big knee blocks. Has a deep seat. Used for dressage. Not easy to jump in!
Once you decide that, I would recommend looking at LOTS of different saddles. English saddles are very precise; they either fit you or they don't. They either fit your horse or they don't.
Some will rock your pelvis out of whack and some will sit you nice and neutral; till you try them, you won't know what feels best to you.
If you would like, feel free to PM me if you have specific questions (I work in a tack shop :) )