SF still has Jon Miller, right? Don't watch many Giants games due to the fact that the team is boring and mediocre. That guy has a great voice.
Most overrated, by far, IMO is Vin Scully. I get that he's old as f*** and he's been the broadcaster forever, but I'm not really thinking about that when he's slowly telling stories about Matt Kemp eating a taco in between pitches. His voice gets on my nerves, too. I know I'm in the minority but I'd throw that out there.