In reply to Frank4short: I've got a 14 year old bike with a mix of Campag Chorus and Athena on it, and to this day it still runs perfectly. My mates and I had long argued about the Campag/Shimano debate, and in our group, we were fairly evenly split. I was, and still am, a Campag ,man.
About nine years ago I decided to build a no-expense race bike (well, as much as I could afford anyway), so I bought a Bianchi Boron frame, HED wheels, Selle Italia bits and bobs and a full Record groupset. Beautiful stuff, especially with all the carbon and titanium. The main thing though was the functionality, something which still gives me no bother at all.
Some of my friends who use Shimano have had problems, especially with the shifters, having had to replace them, whereas the only thing I've had to replace are chains and brake blocks.
Overall, each to his own, but I think Campag functions flawlessly, and looks good too. "Jewellery for your bike", as one friend put it. I have tried Shimano. and didn't take to it. For mountain bikes though, XTR all the way...