clapton unplugged is pretty good...
some that i'd recommend, if you don't have of course
Sticky Fingers - Rolling Stones (one of my personnal favorites by the stones)
Let It Bleed - Rolling Stones
Exile On Main St. - Rolling Stones
Who's Next - The Who
Tommy - The Who
Live At Leeds - The Who (awesome live album)
Van Halen - Van Halen (their 1978 self title release is one of the best hard rock albums of all times IMO...)
Fair Warning - Van Halen (great guitar work on unchained and mean street)
The Wall - Pink Floyd
Wish You were Here - Pink Floyd
Dark Side Of the Moon - Pink Floyd
Led Zeppelin II (you mentioned it, and i think you should get that one cause it's great)
Physical Graffiti - Led Zeppelin
Led Zeppelin IV - Led Zeppelin (if you like their more "popular" songs like rock n roll, black dog, battle of evermore, stairway to heaven ....)
and the beatles albums of course
thats only some...there are hundreds of good albums out there by great bands like the beach boys, the who, cream, stones, floyd, queen...it all depends on what YOU like..