A Link to the Past is the best. That's all there is to it. Opposed to all of the other Zelda games, A Link to the Past reigns supreme. It has everything Ocarina of Time has and more, with the exeption of graphics. But when the game is da bomb, graphics aren't really important.
A Link to the Past takes place in a very colorful and cartoony Hyrule with all of the enemies from the first and second games, much more interactivity, and the same Zelda feel that the first game gives you. There are also many more magical items and puzzles than there were in the first two games.
Of all the Zelda games made, this game gives you the best gameplay, best graphics (exeption is Z64), and most puzzles. It is definitely a must-have for any Zelda fan or collector.