I don't consider myself a hardcore gamer, but I have had nearly every videogame system from the Bally AstroCade (Thanks, Dad!) to the PS2 (Thanks, wife!). I always have the "Latest minus one" video card in my PC. I just like playing games and when I have the chance, I will be racing Tony Stewart in NT 2004 or hunting Charlie in BattleField: Vietnam.
I have been reading a great little gaming site recently, qWirkGames Lite, and feel I need to recommend it to everyone who is not quite hardcore, but just loves playing games.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.