Pokemon HeartGold/SoulSilver

Should I buy the DS (used, b/c I want the advance slot) for  Pokemon HeartGold/SoulSilver ,
 but what othe games do they have out there that are good or even great, Include your top DS games list if you could. 
Also Do you think  Pokemon HeartGold/SoulSilver  is the best pokemon game ever, or what is your favorite?

Should I buy the DS (used, b/c I want the advance slot) for  Pokemon HeartGold/SoulSilver ,
 but what othe games do they have out there that are good or even great, Include your top DS games list if you could. 
Also Do you think  Pokemon HeartGold/SoulSilver  is the best pokemon game ever, or what is your favorite?

i don't have a DS anymore but get mario 64 DS, feel the magic, soul silver, and some gameboy advanced pokemon games.