Gamescore, Game1 --> Funan. Shopkeepers in Gamescore are mostly NDS addicts. Good service. Game1 was under renovation during my trip to S'pore but is reopened coz my cousin bought PSP there.
SeowChoon --> few branches. Went to liang court branch before to help friend get Bleach DS. Service not bad.
Funzcentre --> Located at Ang Moh Kio Centre. Never been there but friend recommended them.
Playboxx --> Located at Tampines. Never went there either but its name often appears in Singapore forums so I guess it's no bad too.
Hate dealing with those in Orchard Road. One of them handed me a Princess Peach when I asked for Bleach DS.

Another told me Bleach is a comic, like I care. And the games(expect PSP games) they're selling are very very limited, exactly like Sg Wang.
Better take MRT to find those good shops instead.