Heart Gold and Soul Silver are great, but you can't go wrong with any of the new ones. Platinum is great, Black and White are great.

I really enjoyed Diamond and Pearl. Probably my favorite of the Pokemon DS games. HG and SS were cool too. I thought the Pokewalker was a fun idea. I'd recommend either of those.

To be honest though, as far as gameplay/originality go, well, they're all pretty much the same. They feature different Pokemon and the stories are all different enough (and mediocre), but at their core, they're all pretty much the same game. If you haven't played a Pokemon game in a long time, I'd probably recommend just going with whatever's newest.

Yeah I'd figured they never diverged from the main idea too much, I was just looking for updates. Like the night/day changes or the seasons, the pokewalker is cool...

I liked the original gold/silver a lot, so I definitely want to get HG or SS. But I also want something new, so for that, yeah, I'm just gonna back up Black 2 I think.