bad_fur_day1: Hmm, interesting.
kusumahendra: since you're interested in Lufia nds
Many have trouble when using a character named Guy because he is slow and it's hard to connect his combo that seemingly to start with a slow bing swing.
He is actually as easy as any other character in the game to use. People who have hard time using it mistook his big swing as his first attack. There is actually a weak kick before that swing. If that kick connects, the rest of combo will connect. Keep that in mind if you decide to play it
Also, the game is not very optimized so in some dungeon you'll experience slowdown. Nothing is game breaking but I think you should know
Lufia II for the GBC is supposedly really good and one of the few RPGs with puzzles, like Golden Sun.
Also Golden Sun 1+2 are the best original GBA RPGs for the system and overall one of the best RPGs for any system you can get because of the story, music, graphics and combat system. GS: Dark Dawn for the DS is also good, but it spoils the GBA games story, which is basically one story in two cartridges.
Boktai 1-3 are totally awesome action RPGs that use real sunlight, so if you don't own the real cartridges you need to patch them to simulate sunlight - I'm missing only the third game which only came out in Japan, however there's a 100%ˇtranslation patch for it, so you need a flashcart or an emulator if you want to play the last game. However the story continues only loosely, each one is standalone, so you can play them in any order and the frist two games are a real blast, I recommend buying the real carts to enjoy the sunlight feature!
AxHell: Everyone already listed the best games on the system. I'll just add a few :
Actually, two of the best games for the DS are missing:
Infinite Space - a totally awesome space scifi RPG, watch the trailer!
and
Suikoden Tierkreis- if you're a fan of the series you might be disappointed as it's in a new world (no cameos or a continuing of the established world) and has a different magic and weapons system, and doesn't have minigames at the HQ, however on its own it's a remarkably good RPG.
Also Lunar Knights are really good if you like action RPGs, it's a spiritual sequel to the GBA Boktai series, minus the sunlight chip. That makes it three.