Pokemon Diamond or Pearl?

[Grey Acumen]

Yeah, depends on what you're interested in.
I hear that Platinum is going to have a bunch of extra content, just like what Yellow was to Blue and Red, what Crystal was to Silver and Gold and Emerald was to Sapphire and Ruby. That's what I'm waiting for myself.

Personally, I'd go for Diamond. I've always had a preference towards the blue spectrum, and indeed, there is also the point where it's less girly than pearls, but as has been mentioned, I have a feeling most people go that route, so it's much harder to find people who have Pearl.