Whatever you buy, get a good quality leather, they will last you many years. A lot of picking out styles and types is personal preference, You want them thick enough to protect you, but now so thick that they are restrictive to move in. Make sure they fit you comfortably and that you can bend in them, and that they are trimmed so that you aren't tripping and stepping on them when walking, but that they still cover your boot when sitting on your bike with your leg on the pegs or boards. I like zippers with snaps over them at the knee and ankle and mid calf. That helps keep them zipped in the wind. I like a belt type of fastener in the front. with adjustments in the back also.
Also are you just going to wear them over jeans or more clothing, like winter riding? Definitaley go with big pockets if you can, It can be hard to get to your wallet and keys that would normaly be in your pant's pockets when you have chaps on. That way you can put those items in your chaps and it makes life easier. Lined or unlined is also an option. I have a pair that are lined and I like them. Didn't mean to rammble but a reputable dealer should help you in fit and function. Sometimes people need to get them custom made to fit at the top of the leg and bottom and waist. Or have the zippers and fasteners moved to make them fit well. Good Luck in your shopping.
