Hey, I've been getting into RPGs lately, and since I've pretty much done everything on my copies of Diamond, Pearl, and Sapphire, I've been wondering if there are any really good ones that you guys would like to suggest. I've also been looking for a copy of Crono Trigger for the DS, but haven't had any luck. So, if you guys know of any really great ones just post 'em here.

Pokemon Mystery Dungeon - Explorers of Sky, Final Fantasy IV and Final Fantasy Crystal Chronicles - Ring of Fates. I would mention Pokemon Platinum, but you already have Diamond and Pearl.

I also see you are trying to get your hands on Chrono Trigger, good boy, good boy.

Bowser's inside story, Partners in Time.

The World Ends With You is one of the best RPG's I've ever played, as well as one of my personal favorites.
If you're into strategy RPG's then you should try out Final Fantasy Tatics A2, Might and Magic: Clash of Heroes, Knights in the Nightmare and Disgaea.
Super Robot Taisen OG Saga: Endless Frontier is quite awesome, and one of the funniest games I've ever played, if you're up for a challenge. Video footage can be found here
If you want something more retro, you can get Ys: Books 1 & 2: Legacy of Ys.
There's also the Mario and Luigi games (partners in time and bowser's inside story.)
I really love RPG's

Bowser's Inside Story? You are lacking in Bowser's Inside Story. jaw51 is Bowser's Inside Story-less.

Contact, Magical Starsign, Sands of Destruction, Nostalgia, Heroes of Mana, Lunar Knights to name a few more I enjoyed.

Contact, Magical Starsign, Sands of Destruction, Nostalgia, Heroes of Mana, Lunar Knights to name a few more I enjoyed.

Sands of Destruction, DQ IV and V (this one is becoming rare though), FFIV, The World Ends With You

Final Fantasy Crystal Chronicles: Echoes of Time
Kingdom Hearts 358/2 Days
The World Ends With You

_{Square Enix FTW on DS RPGs}

Mario & Luigi Bowser's: Inside Story. Enough said.

Chrono Trigger is indeed awesome.

Pokémon HeartGold and SoulSilver are even better than the Sinnoh games. Even though they are just remakes, they are also remakes of the best Pokémon games.

As others have said, def. try and get a copy of Chrono Trigger, that game is classic. And Bowser's Inside Story is a blast too. Both have plenty to keep you busy.

Mario and Luigi Bowser inside story. My first M&L RPG, and it is my fav portable game hands down.

No one has said mario and luigi superstar saga???
Dont listen to everyone else, its way better than BiS
And all the square enix rpgs too, and pokemon

Ok BiS is great and all, I love the game. There are other RPG's on the system though that are great and not just first party Nintendo. I would suggest broadening your horizons. Also BiS is very short compared to a lot of others. Like I said it's a great game, but there is other stuff out there.

...If you get BiS, your enemies will fold like napkins who are crying...

Magical Starsign (very underrated), Bowser's Inside Story, Kingdom Hearts 358/2 days

Without a doubt the single best DS RPG is Chrono Trigger.

You might like Dragon Quest Monsters: Joker.

Try to find a copy of Suikoden Tierkries if you can. It's not a true continuation of the main Suikoden series but it is a traditional RPG with a classic battle system and you still get to seek out the 108 Stars of Destiny. The 2D environments are of high quality, too. I wish I had time to finish it myself.