Well, if we are going to throw camera creds around... currently I shoot a 4x5 Chamonix F1, a Chamonix Saber, a Leica M9 (when I used to have $$...) regularly. I have the XPan II with all 3 lens, and I have a SWC Biogon and a 617 Shen Hao, plus I HAVE shot a Mamiya 7II with 3 lens for almost 2 years...

If I can keep only one camera, it's likely the XPan. I hate shooting landscape with it now because the the 4x5 and 617 are so much better with the huge negs, and the Leica M9 is better for street if only because it's 18MP digital, but the XPan is just the best combo of fun, usability, high image quality, and small size.