Now that Klipsch has (long) discontinued the Promedia 5.1 Logitech pretty much owns the "hi-end" PC speaker market. I've heard the 5500s and they are pretty impressive for gaming. The old ProMedias (when they worked) were better for music. The Promedia 5.1 used an older version Klipsch's
Quintets for the Satellites. If you could find a Promedia 5.1 used (and working) it would rock your world. But Klipsch's BASH amplifier had a bad habit of dieing.
Of course with enough budget I'd go with (and have gone with) a much better system for playing music, but that's not the goal. Gaming is. Honestly, although I haven't listened to it I'd be tempted to try Jinjuku's PE solution if it's within budget. It should provide a good solid basis for future upgrades from a kick butt gaming system into a kick butt gaming
and music system.