Open Your Heart by Crush 40.
I want to get Sonic Adventure 1 and 2 now.
I've played Sonic Adventure 2 Battle a lot and really like it, but I've barely played the first, as I never owned it. If you have a Gamecube or Wii you can get both. Sonic Adventure 1 is available on the Dreamcast as well, but that will be a lot harder to find, and only the Gamecube has the DX (Director's Cut) version.