Listening to the 'Wichita Lineman' (not many better lines than "I need you more than want you, and I want you for all time") puts me just in the mealancholic mood to consider regret .....
The ones that got away are:
Holdsworth Avanti - first proper bike, owned, sold, reowned, rear ended by a double decker on The Elephant and Castle roundabout in morning rush hour, repaired and resprayed, sold on eBay equipped with Super Record for buttons (I appeared to forget that pounds were a suitable currency)
Specialized Stumpjumper - first really decent off roader bought for me by a friend ("I've entered us in the Polaris" "I haven't got a bike" "I've bought you a Stumpjumper, you owe me £625 big man". Even BITD I was a figure of fun), sold to get a Klein, repurchased following a respray, abandoned in Pakistan
De Rosa Titanio - available on eBay, negotiated with owner, decided a bit too much so bought a modern monster instead. I could have owned a De Rosa built by Ugo De Rosa! Idiot squared
The best part of the De Rosa is that it put me in Carpe Diem mode which means that I am bike rich but shed poor (have on a whim bought a Yo, an Inbred and a Racelight. For way less than the modern monster).
So the moral of the story is that it is better to have loved a bike and lost than never to have loved a bike at all
I will weep quietly now.