I want to get both, and probably will eventually, but as for which I get right away and which I wait on I don't know. After watching Smasg Brothers Melee, Cube has jumped into the priority spot. Plus, if I get the two new Zelda Gameboy games, they're still for GBC, so maybe that will satisfy my Gameboy craving.
I'm still blown away by SSB Melee! I just can't get over how absolutely awesome it looks!! (I'm not a graphics man. I'm a characters man, but SSBM has both in full force!)