1. Zelda: A Link to the Past - if you haven't played this game before, this is of course your first choice...
2. ActRaiser - short but great game
3. Mickey to Donald - Magical Adventure 3 (only if you've played Magical Quest first, of course
...Magical Adventure 2 sucks big time, btw)
4. Illusion of Gaia (Coincidentally, I just finished it today...if there's a Zelda-killer on the SNES, this is it)
5. Terranigma (much better than Illusion of Gaia, but also much longer and with more RPG elements than IoG, so I'd play this after IoG)
6. Secret of Mana (probably the longest one of the games in your list, also probably the best one...)
But in the end, it doesn't really matter in which order you play them...
Just be sure not to miss Zelda, Terranigma and Secret of Mana, finishing these should be your highest priority