I'd say go with an HK Compact or Full Size (if you can conceal it). In my opinion they offer the best options for carry (cocked and locked, hammer down unlocked, it has de-cock, everything can be done with the safety on if you so desire) very quick to take apart and clean. It's a safe, reliable gun.
My only complaint for the sig is weight, I would trust it just as I would an HK.
Glock... well. I don't paticularly like them, but I have nothing against them except for the disassembly procedure, which as I understand requires one to pull the trigger. I've fired them on several occasions and found them to be excellent firearms.