ooooh! I took english riding lessons for ages-I looove it!! I agree, basic equipment would be boots, pants and a helmet. (I never wore gloves) Personally, I prefer the lower paddock boots to the full length riding boots. The full lengh ones you'd need if you got into mid level/advanced showing, but IMO shorter is better. A great website is State Line Tack. I hope you have a great time with lessons! Jumping is so much fun!
Androidbeing, There are both differences and similarities between english and western riding. The most obvious difference is the tack the horse wears.
The western saddle is larger and heavier than the english saddle. It's designed to spread the weight of the rider over a larger area of the horses back, making it more comfortable for long days out chasing cows.
The english saddle is smaller and lighter and designed to give the rider a closer contact with the horse's back.
With both the english and the western saddle, different designs are available to accomodate certain styles, sports and disciplines.
As far as riding goes, the main difference between english and western riding is that in english riding, the rider takes a direct contact with the horse's mouth via the reins and uses the reins as part of the "aids" (along with the seat and the leg) for speed and direction. Most western riding horses are ridden on little or no contact and the rider uses his seat, his weight and neck-reining to give aids to the horse.
The position of the rider is much the same in both english and western. The rider should sit tall and straight, leaning neither forward nor backward. The rider's legs should hang naturally against the horse's sides and the arms should be relaxed and against the rider's sides (flapping elbows are frowned up in both disciplines).
In english riding, the rider takes a rein in each hand, whereas western riders take both reins in one hand, allowing the other hand to fall naturally at their side, or lay on their thigh.