I am considering putting either the Sightron SII 3.5-10x42mm, the Mueller TAC II 3.5-10x44mm or the Pentax WTU 3.7-11x42mm on a new 7mm-08 that will be used for deer, antelope and elk hunting in open country. Optical clarity is my #1 priority, as most of the shots will take place in ample light.

Which would you all recommend, and why?

I have never much liked Pentax scopes nor seen Muellers, but I assume they are o.k. Every Sightron I've seen had great glass. I'd go with Sightron myself. Others to consider would be Leupold VX II or III, Weaver Grand Slam, Burris Fullfield II and Bushnell Elite 4200. Good luck in your selection.

Seattle: I think the Pentax scope you listed is the white tails unlimited, right? This is a great scope. Although I am much more impressed with the lightseeker series, but that is more expensive.
Although I have not had hands on experience with the Mueller, that would probably be my last choice. this is because of some of the lukewarm buzz I have heard on the net.
My vote would go for the Sightron SII series of scopes. I have some sightron optics and I feel the SII is the best scope for the money in the200-350 range. The coating quality is excellent, and they are fully multi coated with no less than 7 coats. The windage and elevation system (called, I think, exact track) is reputed to be one of the most stable on the market in any price range. I have not been able to get it to shift. But I just got a new Sightron SII 3-9x42 w/o the adjustable objective. I am putting this scope on one of my 30 cal magnums and I will see how tuff the exact track is. With the 7m 08 I don't think you will have excessive recoil.
But Penatx is also a great choice, and I use some of thier optics too.
let us know what you get
okcmco

OH yeah. And I agree with BugsNbows! The Bushnell elite 4200 is a great scope as is the Leupld VXII. So is the Burris Fullfield II. I have heard that Burris and Pentax are made in the same factories in Japan and America (the Penatx Lightseekers, and Burris Signatures are U.S. made although who know where the glass is made).
For the price of the Leupold VX3 you get into alot of middle tier scopes (Zeiss Conquest, Sightron S3, Nikon MOnarch Gold, IOR Valdada, Meopta). It is a crowded field and though to choose.
And YEAH! The weaver grandslam is a truly excellent scope!
If they were all free, I would take the Penatx Lightseeker/Burrris Signature. But they are not free so I am a big fan of sightron