First LP: can't remember if it was a punk album of some sort, or Led Zep IV (mom had a decent collection, so i started from a good place)
First cassette: Bryan Adams "Reckless" (first music i ever bought, using a gift certificate from my aunt)
First CD: Ozzy "No More Tears"
First 45: i can't remember ever buying one... i collected a few that were given away, freebies, etc.