The expert chefs say, ditch the press and smash and mince. I've tried to smash and mince garlic but nothing beats my Pampered Chef Garlic Press. What's your must have kitchen gadget?
This may be something too small to call a "gadget", but I love these magnetic measuring spoons. They nest like a normal set but stick together in the drawer so you never spend a minute looking for a missing one that moved to the wrong spot. There are about a million varieties on Amazon and elsewhere.
A couple of my choices were already mentioned (microplane and mandolin) so here's another worthy addition. If you like pepper as much as I do, your regular pepper mills drive you insane with their measly output. Insert the UNICORN!