road bike aside, i've ridden almost exclusively on flats for the last couple of years...
after 'quite a few years' of mountain biking i've been through (and avoided) quite a few fads, when i got my first 'serious' bike with suspension forks (rockshox mag21) i was told i needed a 0 degree rise stem to make up for the added height (with 21" flat bars of course) - i fell off that bike hell of a lot, then i got an off the shelf marin with a mad 10 degree rise stem, and was much happier
so all my bikes from there on had stems with some rise, then came riser handle bars, and when i finally got some, i was much happier on a bike
clipless - i've been there, first pedals were some early shimano hand grenade style jobs, then time atacs (which lasted ages), looking back i was never that happy with clipless, but stuck with them because thats what 'proper bikers' used
a couple of years ago i fell off and stayed cliped in, luckily my very worn out shoes broke rather than my ankle, so i rode out of necessity on flats, and really liked them
for the last couple of years i've really got into ridding flats, i could anaylise this and that, but basically i just have more fun on flats (even being a jey xc'er)...
...recently i've taken steps to really up my fitness, so felt the need to go back to clipless for up coming races, but try as i might i just don't feel as comfy, so sod it - i'm going to race XC next year on flats 
(not like i'm going to win)
