Westwood's Eye of the Beholder 1 and 2 remain today two of the best real-time RPGs ever produced.
They feature great graphics for their time, tons of cool weapons and devious real-time puzzles that mysteriously make you come back for more traps and pressure plates to push. The plots are typical kill-the-big-foozle fare, but the games are so well implemented that you'll be glued to the screen for hours on end. The graphics and animations are both top-notch, and excellent sound effects add to the incredible "you are there" atmosphere that is rarely achieved in RPGs of that time.
Although EOB 2 feels at times like a poor rehash of its predecessor due to awfully similar graphics and monsters, it does feature more expansive and varied outdoor levels, as well as less frustrating endgame boss (defeating the Beholder in EOB 1 is nearly impossible if your party is not at maximum levels). They're both very challenging games that are definite must-play for dungeon-adventurers, especially fans of book-based AD&D. Too bad SSI's own EOB 3 doesn't measure up to these classics.