The god of time (aka Doc Brown's nightmare Pokemon) is none other than Dialga, a steel/dragon-type that is also the mascot of Pokemon Diamond, and - again - is literally THE GOD OF TIME. You'd think the god of time - which is also a metallic brontosaurus - would place a little higher in any list, but then again, this is Pokemon we're talking about, and we haven't even gotten to the fire monkey yet. Speaking of...
Infernape is the 2nd fire-type starter that ends up as a fire/fighting-type, thus starting the worry amongst many that "oh shit, is every fire-type starter going to end up fire/fighting?" Gen 5 would respond with a clear "HELL YEAH!" with a wrasslin-pig (that eventually Generation 6 would back away from). Still, Infernape is an incredibly great starter - cool name, cool type, and a burst of flame for hair. Plus, monkeys on fire are more dangerous than ones not on fire.
For the first time in these toplists, a water-type has topped a fire-type starter. Appropriately, it's the Emperor Penguin Pokemon Empoleon that rose above the ranks and came out on top. Empoleon is a nigh-unkillable Antarctic steel-bird - it has a huge number of resistances, can be an incredible HM-slave if you want (and if so, shame on you), and is generally a great choice for your starter. Like some kind of inverse March of the Penguins, except Morgan Freeman is in awe of how badass it is instead of how likely it is to die.
The only ghost-dragon in the entire Pokemon series is none other than Giratina, the last member of Sinnoh's creation trio, representing antimatter - the only quantum physics Pokemon (maybe it should be Neil DeGrasse-type?). Pretty impressive, especially considering it looks like some kind of centipede-dinosaur out of my own terrible nightmares and sounds like it should be a giraffe (that's Girafarig though).