In the North West of England, the ones I have done and would recommend:
1. Walna Scar
2. Parkamoor
3. San Marino descent (Winter Hill)
There have been loads of other recommendations of here, quite often from SFB and the Bogtrotters lot, who have some great routes around the Lakes. I've got some on my 'list' for this year.
Looking slightly further afield, then I'd definitely include Snowdon Ranger path, although its a big push up there and loads of cracking stuff around the Dark Peak: Edale Cross to Hayfield, Beast, Potato Alley, Lockerbrook, Cavedale, Cut Gate, Chapel Gate, Rushup Edge. Not wanting to diss the Peak, but if you are after big, steep, rocky descents then Lakes or preferably MUCH further north will be better.