I have a totally mint copy of the Beatles White Album on vinyl that I have been told is worth a fair wedge of money, although I have never looked into it - it was given to me on condition I never sell it.

As far as techno goes, I once owned a copy of the original pressing of Jaguar, but it was stolen along with a number of other great tunes. I don't even know if it was worth anything more than what I paid (£10), but the thing that really pissed me off about it is some asshole smackhead probably sold it for 50p.