Absolute best game:
Castlevania: Aria of Sorrow
Great games:
Metroid: Zero Mission & Fusion (Although I much prefer Zero Mission)
Castlevania: Circle of The Moon & Harmony of Dissonance
Sabre Wulf (Yo Paladin!)
Hajime no Ippo (It's probably the "punch-out rip-off" mentioned earlier)
Ougon No Taiyo - Golden Sun (The second one is very good aswell)
Zelda: Minish Cap
Ninja Cop
Double Dragon Advance
Kuru Kuru Kururin & Kururin Paradise
Iridion 2 (Pretty much better than it's predecessor in all ways, even tho the first is an okay game)
Lufia - The Ruins of Lore
F-Zero GP Legend
F-Zero Falcon Densetsu
Worthy mentions:
Kirby Advance
Kirby And The Amazing Mirror
Kirby Nightmare in Dream Land
Tales of Phantasia Advance (No this was never released overseas until the GBA copy)
Sword of Mana
Shining Soul 2
Lady Sia
River City Ransom EX
Turbo Turtle Adventure
Mega Man Zero 1,2,3,4
Final Fantasy Tactics Advance
Tales of the World - Narikiri Dungeon 2 (sadly u need to translate this via patch)
Simple ports, but great games:
Breath of Fire 1,2
Final Fantasy Advance 4,5,6
Final Fantasy 1&2 - Dawn of Souls
Comix Zone
Contra
International Karate Plus
Donkey Kong Country 1,2,3
Sonic Advance 1,2
The Legend of Zelda 3: A Link to The Past