happens a hell of a lot for me.
i blame downloading culture acually. i snap up teh 4 or so tracks that always leak early, and because everyone else gets a torrent or whatever, and starts talking about it, the actual impact of the release date is completely nullified, so i don't end up getting it.

anyway, from recent to old:

Bjork - Volta. was really excited about this. still only heard Earth Intruders

Arcade Fire - Neon Bible. got a few advance leaks, saw them do it live, never been bothered enough to listen to the whole thing

and the grandaddy
Reuben - Racecar is racecar backwards.

i was pretty obsessed with this band for their first few singles. i was in one of their videos. i used to ask rich people i knew to set up record labels to fuind their album recording.
probably cos they took so fucking long about it, but i've never even seen teh record

there are probably, many many more. like lou reed's edgar allen poe one