Helloween - Keeper of the Seven Keys (pts. 1 & 2 - need to get both albums as a set - these are some of the most influential albums on the European metal scene. Classics in every sense of the word)
Manowar - Kings of Metal (not my favorite Manowar album - barely gets beaten out by "Triumph of Steel", but this is probably thier most "classic" in terms of style and substance. And it also features some of their best songs ever: Hail and Kill, Defender, Crown and the Ring, etc.)
Iron Maiden - Powerslave (tough choice here, as the band has so many great albums, but this one wins out for some memorable classics, i.e. Powerslave, Rhyme of the Ancient Mariner, etc., and it's all around great production values)
Virgin Steele - The House of Atreus: Act 1 (First of a two part album set, this is an awesome blending of traditional heavy metal with operatic overtones. Great stuff, and the them of Greek mythology kicks ass too! wink )
Iron Savior - Iron Savior (first of their albums, and still the best. European power metal at its finest)
Iced Earth - Horror Show (great "concept album", where all the songs are based on the classic Hollywood creature features: Dracula, the Wolfman, the Mummy - they're all here. Combine that with the Iced Earth "style" and you've got a winner on your hands)
There's more of course, but these should be a good place to start for any true metal fan. buttrock