I had a strict full length albums only policy when I started this list but every rule needs an exception to reinforce it's validity and Superfuzz Bigmuff might be officially an E.P. but it's too good to miss off my list.
When Mudhoney's self titled full length LP arrived a year later it was a bit of a disappointment but this 6 track 22 minute "mini-album" had already nailed the Mudhoney sound. Superfuzz encapsulated everything great about the band and is undoubtedly one of the seminal releases of the Grunge era.
I've often felt the extended version that emerged in 1990, combining the original EP with Mudhoney's brilliant early singles, would have been a much better first album. I was lucky enough to see the band play that version in full at the Camden Koko in 2005. It was a blistering gig even if Mark Arm seemed a bit pissed off that they had to play Touch Me I'm Sick first to conform to the ATP Don't Look Back series rules of the original album in full and in order.