A couple of further comments:
On tire width -- I agree with BW, except that before you go wider, you need to check out the weight of the new tire compared to what you're replacing. Depending on the tire, there can be anywhere from 100g to 200g + difference (1/4 to 1/2 lb!) between, say a 2.00 tire and a 2.20 (check out the specs on the Kenda Karma to see for yourself). If you're trying to keep the weight of the bike to a minimum, then adding a half-pound to each wheel can really make a difference to acceleration, energy input, etc. On short, technical rides this is probably fine, and the benefits of a wider tire would far outweigh (pardon the pun) the drawbacks. OTOH, over a long cross-country ride, that extra weight will really make itself apparent in the last hour of the ride. Even more so if you are doing multi-day rides back-to-back. By Day 3 you will wish you had lighter tires -- I learned this two years ago when I rode with my Father-in-law on Vancouver Island -- three days of open-trail XC riding, 3 hours per day, with all-mountain tires that weighed about 800g+ each (~1.5 lbs). After Day 2 I was ready to go straight to the nearest shop and put on some Kenda Small Block Eights. Bottom line -- pick the tires that suit where you ride, and for how long. Maybe keep two sets and swap em as needed: one for long XC rides / smoother terrain; and one for more rugged terrain / shorter rides.
On pedals -- I use the Shimano M520, which I like. Open design sheds the mud; easy to click in and out. Terryl has the M505, but I am going to change these, as they are a closed design and the mud really gets packed in there. Slightly heavier too. Will probably put M520 or M540 on her bike. Ditto BW's thoughts on Crank Bros -- all the riders here that I have talked to hate them. They're light, and look kinda cool, but are a major health hazard as clicking out is not easy. Not sure if that is true of all their pedals, or just the Eggbeaters.