Best All-in-one zoom lens (everyday / travel)?

I'm looking for a good all-in-one zoom lens for everday / travel shooting. I have a Canon Rebel XT and curious which of these three lenses will give me the best bang for the buck:

1. Canon EF-S 18-200mm 1:3.5-5.6 IS (http://www.dpreview.com/previews/can...00_3p5-5p6_is/)

2. Tamron AF28-300mm F/3.5-6.3 XR Di VC (Vibration Compensation) LD Aspherical (IF) Macro (http://www.adorama.com/TM28300VCEOS....21111371119264)

3. Sigma 18-200mm f3.5-6.3 DC OS Zoom Lens - 0.25x - f/3.5 to 6.3 (http://www.jr.com/sigma-lens/pe/SGA_CA18_hy_200OS/)

Thanks in advance for your help!!

Of those three I would go for the Canon 18-200 IS.

I'd go with the Canon as well. However, if money is an issue and you're on a budget, there's no denying that Sigma has upped it's game to compete directly with Canon on their lenses. Photography magazine and others have been giving Sigma extremely high marks when it comes to value vs. quality and a few have flat out said that they give the Sigma the edge. That's saying something.