Adding to the chorus, not to worry too much about the weight of your bike.

I had a friend who raced. One day out on a training ride, he came upon this guy. Pulled up next to him and tried to strike a pleasant conversation and the guy was not too amused with my friend. My friend noticed that the fat-tub-o-lard had a lightest of everything on the bike. And they were climbing hills. The guy appearently was really rude to my friend, so my friend said "hey I know what you can do to go faster" to which the guy said "huh?" My friend grabbed the guys seat post shook the jerks bike pretty hard and said "LOSE SOME WEIGHT" and sprinted up the hill. My friend was a seniors CAT-2 at the time.

If you are bit overweight. Skip that icecream, treats...

If you want to "jump" out of a corner, then you will notice a difference with lighter mass wheels as DebW says.

I think its silly to use titanium skewers, titanium bolts and what not. If you are that rich I guess you could be dumb about spending money.

BTW, I told my friend that what he did wasn't nice. Just enjoy the bike you have lose a pound and you'll be saving thousands of $$$

Speaking of whjich I need to lose ahem cough cough pounds...