Which Pokemon to Get?

Okay, I have a DS but I have woefully neglected it since I got it, which I'm ashamed of...

Anyway, I haven't played a pokemon game since like, Silver or Gold when they first came out for the Game Boy. With Platinum, HeartGold and the new other new one out, which one would you recommend? I'm also considering some Mega Man or Castlevania game since I haven't played any of these newer versions on the DS either. Thanks!

Try posting this in the DS Recomendation Thread ;)

But as a side note, don't get any of the Mega Man Star Force games... utterly awful.