Monkey Island (only if Ron Gilbert was involved; a new adventure series by Gilbert would be much more interesting though)
Grim Fandango
Maniac Mansion
Full Throttle
Space Quest
King's Quest
The Legend of Kyrandia
Broken Sword
(or rather: more new adventures by developers who are on the same level as the people who created the a.m. games)
Privateer
Ultima
Ultima Underworld
Lands of Lore
Master of Orion
Syndicate
Dungeon Keeper
Magic Carpet