I think getting off the SD would be great - it's chock full of allergens. What are you hoping to go for - kibble, canned, home cooked, or raw? From there, I'd have several suggestions.
If kibble is your dealio - I'd probably suggest Natures Variety Instinct, Orijen 6 Fish, Wellness, Evangers....if you could get some of the same brands in canned and mix w/ kibble, even better. If you could stay away from chicken for awhile, even better.