Reggie to Paris: I'm Single, Let's Party!

Reggie Bush has been single for less than a month -- and he's already partying with Kim Kardashian's arch-enemy ... Paris Hilton!



Bush and Hilton lets the sparks fly at Tao nightclub in Vegas this weekend -- we're told Hilton's man, Doug Reinhardt, was nowhere to be found.

What happens in Vegas ... is definitely gonna piss off Kim.