I realise this topic has been going for ages but as a user of everything from crappy Benelux and Simplex in the 60's to sublime Campag Carbon Record 10 now, I've used the lot. At the end of the day you get what you pay for and there is nothing but personal preference between Campagnolo and Shimano if you take their relevant groupsets head to head. I presently use Campag Chorus on my touring bike and Record on my race bike with Shimano (what else) on my mountain bike. Previously I've used Shimano Dura-ace, Ultegra and 105. With Campagnolo it may be a bit more difficult to set up the gears to change sweetly but once you have, you are rewarded with quick, precise, crisp changes, although there are those who prefer the soft almost imperceptible changes associated with Shimano. This probably just means that Campagnolo is engineered to closer tolerances. I went for a short tour in the summer and realised that at the age of 54, despite the number of bikes and set-ups I've had over the years, I'd never actually used a touring bike fully equipped with campag before. I rode a Thorn Cyclosportif fitted with Chorus 10 and it was the most enjoyable, rewarding and trouble free ride I can remember. Lance may win Le Tour now on Shimano but before him, Campagnolo had won them all bar the odd incursion by Mavic. As the icing on the cake, Campagnolo equipment is finished like jewellery and the feel good factor over the more functional appearance of Shimano is palpable.
Finally, I may be a sad old git but I'm not so sad that I'll be thinking about buying spares 6 years after the components were last made. Anyone who is needs to get a life and a new bike! Talking of which, if I have time to write to forums like this, maybe I need a life to!!