My 10 or so must have trees:
Carrie: Taste, disease resistance, and manageable tree.
Sweet Tart: Taste, Productivity, disease resistance.
Bailey's Marvel - Taste
Lemon Zest - Taste
Rosigold - very early season, productivity, manageable tree
Venus - Taste, productivity, disease resistance
Cotton Candy - Taste, productivity, seems to have good disease resistance at my place first two seasons fruiting
Fruit Punch - Productivity, Taste, and looks like good disease resistance at my place
Pickering - Productivity and tree size
Lemon Merengue - Taste, productivity
Honey kiss - productivity, tree size, late season
Keitt - Taste, productivity, manageable tree, latest season
Dwarf Hawaiian - productivity, tree size, early season