Holy crap, building a decent team in the Sinnoh games is hard. All of the Pokémon I want to use require items, trade, or, even worse, trade with items to fully evolve. You can build a decent team without these kinds of Pokémon but the things available, especially in Diamond and Pearl, aren't to my taste.
Right now in my Platinum I planned a team of Infernape, Roserade, Magnezone, Yanmega and Mamoswine, just need a Water-type to counter my horrible weakness to Fire, but the options are meh... My wildcards in situations like these are Gyarados and Vaporeon, which are themselves very competent indeed, but I wanted to use something different this time.
Maybe I replace Mamoswine with Quagsire and add Weavile as the final member of the team, but good lord, I'm really having to use things I'd never even thought I'd use before. Yanma and Quagsire, lol. but it's all cool, they're Johto Pokémon at heart and Johto is my favorite region.
Anyway, the journal... Currently going to face Roark with Monferno, and Monferno only.