If you already have a PlayStation 3, you may want to hold off on getting an Xbox 360. Both systems generally see releases of most games, and they both generally look and play well on either of the two systems. Additionally, both the Xbox 360 and the PlayStation 3 retain the more important multimedia capabilities (such as movie stores, DVD playback and Netflix). Unless you’re truly in need of play the exclusive Fable or Halo series, you should have no problems sticking with Sony.
It has recently been announced that on-demand ESPN will be brought to the Xbox 360, and nothing has been said about its possible appearance on the PS3. However, because this is still an unreleased service, it’s impossible to determine whether or not this could influence your decision.