Well I use pads in the Peak District! (call me a girl if you like..lots do )
Kneepads... something like Dainese Kneeguard Revolution - you can put them on/take em off with out taking your shoes off - quite good in that you can strap pads to camelbak for climbs or flat bits and then quickly slap em on for the downhills etc
elbowguards.. anything really, I don't think they're as critical comfort-wise as kneepads.
You only realy need to pad up if you are trying things which are out of your skills level and are likely to take a fall.
Hmm I disagree a bit. I wear pads because I know that even riding within my skills level I'm likely to stack it at some point. Riding mostly sharp , jagged rocks I know that that some point will be some point, literally.
Hence forth and not withstanding, t'other month my pads very much saved me from A&E and two split kneecaps when I went over the bars on "the beast" in t'peaks.