Singlespeeds, 29'ers, etc.
I have an old frame that I converted to one speed. Fun, light and simple...yup. Kills my knees and most of the Front Range trails being brutal...yup. So I have not been keen to convert completely. Being a kid and probably in much better shape, that might not be an issue, but I grind my granny gear going up Falcon and Deer Creek and lots of places. Even shaving 5 or 6 lbs doesn't make a 34/20 gear any easier. I like that 22 tooth front!
Are 29" wheel the future? Nah, the 26" wheel still has advantages. First and foremost they are significantly stronger. The 29" wheel also means all your gears are something like 10% taller, so low gears aren't nearly as low as before. So if you like 22/34 or 22/32 in granny, with a 29" bike it's more like pushing a 22/30 or 22/26 (i.e. 3rd and 4th or so rather than 1st and 2nd in the rear cassette). Mostly it's not a big deal, but something to consider. Also 29" bikes will usually have a longer wheelbase, so switchbacks are just a bit tougher. The upside is that they apparently will roll over anything like a steam roller. Also right now the 26" tire selection is 10 times better than 29" tires, but that's changing quickly. But I dunno, I'm still running 26" wheels and it seems every time I get started saving for a new bike something happens to eat up my savings. New truck engine, Kirsten's tuition, taking a month and a half to be with my family. I just can't seem to get past $500 in the bike account.
Pedals. I run SPD, never had an issue. Lots of people like Eggbeaters and Time. Personally Time are fine but since I have all these common pedals to convert would mean 4 sets of pedals or another pair of dedicated shoes. So I just stick with what I have. Eggbeaters are light and reliable, but I found they are just too small and any more than an hour my feet get tired due to the lack of support under the soles. YMMV and it certainly does depend on the stiffness of the shoe (I run SIDI Dominator 5). For after work rides that would not be a problem and certainly for 'cross rides it would be OK.