Which is the best handheld game console?

Can anyone tell me which handheld game system is more interesting? Gameboy Advance? Nintendo DS? Sony PSP? And also, hoh. Where can i buy games online in Malaysia. I dont have time to scour game shops. Best if they accept Paypal of course. I heard that Nintendo DS is notbad. Any user reviews for me? Sony PSP reviews also welcome. But i know that thing pricey lerrr. Rm1.2k wohhhh.... worth it meh???