Platinum was my favorite Pokemon game, and both of my playthroughs of it were quite interesting.
On my first one, after grabbing Turtwig, I initially had both Bibarel and Kricketune on my team, but they fell so horribly behind the rest of the members that they were eventually ditched. A shame because I actually really liked Bibarel's design despite all the hate he gets. I picked up Shinx early on, who became my favorite 4th gen Pokemon upon reaching her final evolution. Anyways, I ended up hacking in a Mantine and a Mew around the 3rd badge or so because I really wanted both of 'em. I met some dude online who randomly gave me an Espeon. I picked up a Sneasel on the way to the 7th gym, but he stayed boxed for a whole minute. I normally don't use legendaries, but I liked Giratina's design enough to make him a mainstay, too. Playing through without a fire-type made this game ten times harder, especially when facing Bronzong. I ended up losing to Cynthia due to a mix of luck-hax and being unprepared. I decided to retrieve and evolve the Sneasel, and reluctantly replace Torterra with him. I liked Torterra a lot, but he wasn't doing much besides dragging my team down due to falling behind in levels and his quad-weakness to ice, which damn-near every Pokemon seemed to carry. Weavile ended up making all the difference as I whooped the champ this time around. The team I finished with was:
Luxray
Mantine
Mew
Espeon
Giratina
Weavile