These are excellent, but be warned the first ones are really difficult find on anything besides Amazon or other online marketplaces, and they probably won't be cheap.Tinkotin said:Phoenix Wright games.
The World Ends With You is awesome and highly recommended for actually being pretty unique and fun.
Bowser's Inside Story: Fun. A little gross if you overthink the concept, but otherwise fun.
If you can handle gratuitous amounts of grinding, Shin Megami Tensei: Devil Survivor is good. But seriously, TONS of grinding. Be warned.
For GBA cartridge games:
If you can find the earlier Mega Man battle network games (1 to 3 or 4 are the good ones), do so. They're a bit kiddy in plot and dialogue, but have an awesomely fun and addictive combat system. Also some of the dialogue is unintentionally hilarious.
Super Robot Wars: Original Generation and Original Generation 2
Awesome mechs? Check.
Cool strategy game? Check.
Mind blowingly awesome music? Check.
A character with music so awesome it overrides the boss themes? Check.