flash cards for gba/ds - which one?

My bro has a ds with an express card, I have an advance sp and want a card for it
but dont know where to start, basically it needs to play all advance games on sp and ds
(as my bros card doesnt do advance games only ds, so we can both use it...)
which is the best one for this (and value for money and homebrew stuff and all round best best card ever? ;) )

Why would you want to still be using that ol' advance SP for? ;P

Hey I like my sp!
Still loads of rpg's I haven't played on it yet.
Yet another question:
What do I need to play snes roms on ds?
Already got the express card with moonshell........

I would go for the M3 adapter, because that's what I have. I waiting about half a year, saving up money and researching it. (www.m3adapter.com ::))

For slot1 go with R4DS instead of M3DS. The M3 is just a rebranded R4 so might as well go with the original. :)