I bought Wind Waker WITH my Gamecube, on the day of release, solely for that game. Now it's the console I have the most games for, and the most games that I replay and enjoy.
I bought my GBA SP in order to play Final Fantasy Crystal Chronicles, and I didn't actually buy any games for it until several months later.
I half-bought my PS2 in order to play FFX, but shortly before buying it, wanted to get MGS2 as well, and I did so since both FFX and MGS2 were cheaper when bought with a PS2.