Beautiful life [ビューティフルライフ] This drama is probably another top 3 I've seen...music is good, story may be sappy (like most dramas), but gives an aspect from both views of the main chars...
Densha Otoko [電車男] Great drama, funny as hell and shows different views of being in love...from Otaku to pride for a hobby.
Koishite Shinitai [恋して死にたい] The drama that 1st got me into J-Dramas...old, maybe overrated, but this is the one that got me hooked.