I recently ordered Metroid II: Return of Samus off ebay and am playing through it when the Wii is not available, and when it is I usually play Metroid Prime 2: Echoes (You can tell I like Metroid

). I occasionally play Metroid Fusion, or Metroid Zero Mission when I get bored with Metroid II, or I play Golden Sun.
Recently I went to a local Gamestop looking for Metroid Fusion, and it was only $5! They also had Advance Wars 2, Golden Sun, and Drill Dozer. I bought Golden Sun (for $7) and Drill Dozer ($5) because I recognized that they had assist trophies in SSBB but I had never played them and because they were so cheap. I also bought the Advance Wars 2 ($5) because it was supposed to be fun, but it turned out the copy I bought was a flash cart that had a Advance Wars 2 ROM on it, and it would not save correctly so I had to return it in exchange for Final Fantasy 2. I didn't care for drill dozer or Final Fantasy that much, but I like Golden Sun.
So in other words I'm playing:
Metroid II: Return of Samus, Metroid Prime 2: Echoes, Golden Sun (and I also occasionally play Metroid Prime Hunters but I don't find it as fun)