Yeah, I have spent a lot of time on weightweenies.starbike, but I'm not exactly sure where to start, because I am not as familiar with the products themselves in order to judge what is worth upgrading to.
My first problem is that I don't even know what my frame and parts weight and I don't have a scale
Anyways here is my spec:
Custom bike by Marinoni, 52cm Columbus SLX frame and fork
Shimano Ultegra headset, 1" threaded
3TTT alloy stem (unknown model)/3TTT Forma handlebar
Shimano 105 STI, front and rear der, 8sp cassette (12-23), crankset, brakes
Shimano PD-6500 (old ultegra) pedals
Shimano 105 hubs/DT straight gauge spokes (Champion?)/Campy Moskva rims
Hutchinson Excel tires 700x23 (heavy, but cheap

)
Bontrager Super Light tubes
SRAM PC48 chain
Kalloy seatpost
Selle San Marco Strada saddle
I would most likely think about new wheels because my hubs are toast anyways. Good wheels are expensive though. I don't know how much weight a carbon fork would save, but I think it may be possible to find a deal on eBay since 1" threaded is an obsolete standard now.