If you are looking for summer weight (oh! if only it were summer - got hailed on yesterday) the Jeffries competition breeches are nice. Make sure you get the full seat ones. They have a grippy bit around the calf which is much more comfy than velcro.
I like Jeffries competition breeches and the old style Premier Equine full seat breeches. PE have changed the style so I'm not sure about the new ones but I get so many complements about the old ones and they are very comfortable so I'd be surprised if the new ones were too different other than they are now higher waisted which I'm not keen on.