Giovanni. I mean the reason why the name is so cool sounding is because it's got a nice pattern to the syllables- it has a stressed syllable, then an unstressed, stressed again, then ends with an unstressed. It's fun as shit to say. I personally love that "io" or "eo" sound in words, for instance that's why Romeo is so fun for me to say. I also like the hard "v" sound.
Even though pokemon characters where really hollow and not really developed at all, Giovanni -the leader of team rocket- was the fucking coolest because he was the main bad guy and his name was so neat it sorta told you everything about him in a way without him having to actually doing anything. Like if you're poke-battling a guy named "Giovanni" you better have packed a shit ton of Super Potions, you fucking *****.