Stop in for an espresso or cappuccino at the opulent Café Cordina (a local and tourist hangout near the Cathedral on Republica Street). I suggest you pass by all of the tourists sitting outside and instead have your coffee the local way: standing up. Pay for your drink first at the register and then walk to the old metallic bar and provide one of the bartenders your ticket. They will whip up your cappuccino and you can stand there and drink it among the locals who are popping in between meetings for a caffeine jolt.
Valletta in a Day.