I really wanted a light bike back in the day but could not afford to go nuts with all the pimpy bits or bolt kits. It was expensive enough to keep my bike going with all XT.
I bought the Trek OCLV bacause I was racing and it was super light - but I broke 2 in six months
I drooled over Aluminium and Titanium bolt kit but never bought them. I did run latex tubes for a while and always used DT revolution spokes, I even had alloy nipples on a front wheel
Due to the terrain I rode/ride running 2.1" Smoke and 2.2" Dart tyres was the way to go - I tried smoke lite's but 6 punctures in one ride was enough for me.
A few years ago I finally got a bike under 20lbs by throwing away all the gears, suspension, bar ends, etc and running silly light tyres. It's not my everyday bike so I can get away with such stupidity
Light bikes rule (but only on the right day in the right place)
He's not the messiah, he's a very naughty boy.
95 Kona Explosif Singlespeed/Fixie - 100% Thrashed since new and it's still very well loved (and it looks it).
Dave Lloyd C.A.T.S W.I.S.K.A.S - Built, ridden, loved, and sold.