Two separate things, I think.
Life changing is hard to decide on just one, because several came out in 1977 that totally changed what I listened to. I was 14, and all at once Elvis Costello (My Aim is True), Talking Heads (77), Ramones (Rocket to Russia), Sex Pistols (Never Mind the Bollocks), The Clash (The Clash) were released. Sure some of them had done earlier releases, but that wave of new music hit my rural small town in 1977 and it shifted me from a Top 40 background (pop and disco mainly) into one that sought out different styles.
Over the 45 years since then, the result is I've developed eclectic tastes liking almost any style as long as the artist is exceptional at their chosen style. Some of my favorites now include metal (Motionless in White), pop (Taylor Swift), P&W (Hillsong United, though I've had a recent fascination with Maverick City), country (Sugarland) and good old rock (Nothing More).
Favorite album of all time? I think I'm going with David Bowie's "Young Americans", but it's more of a throwback thing currently. Hillsong United's "Empires" and "People" have both gotten many more plays from me over the past several years.