- Is the B+W UV Haze a "good" filter to choose for the 17-40 and 24-105?
Highly recommend B+W (I have them on almost all my lenses), make sure you get the MRC or Nano versions of the UV/Clear filters. For a dSLR, there is no difference between UV and clear, so get whichever is cheaper where you shop. If there's a chance you'll be stacking another filter on top, get the XS-Pro mounts - that's a thin mount that still has front threads for the lens cap or another filter.
- Should I consider a CP filter for my 24-105?
I think so - a CPL is one of the filters where the effects cannot be reproduced in post processing (others are ND and grad ND). Since the 24-105mm and 17-40mm both take 77mm filters, you can use the same one on both.
- If I put a CP on my 24-105, is that just for outdoor photography would I remove it for indoors, take it off and on depending on conditions?
Yes, you'd generally remove it indoors, with some exceptions, and not always use it outdoors. A CPL will cost you about 1.75-stops of light, so there are lots of times when you won't want to use it. But even indoors, it can be used to cut reflections from glass/water, etc.
- Would I stack a UV with a CP filter?
Generally, no - stacking filters is not a great idea, although the optical hit is slight with high quality filters, why do it if you don't need to? More importantly, sometimes filters get stuck together. That's less likely with B+W's brass mount rings, but it can still happen. Get a set of filter wrenches, just in case ($5 plastic item from B&H/Adorama/etc.). I do sometimes stack the CPL on a UV (which I have on most lenses), if I'm in a hurry to get a shot. If I'm setting up a landscape shot on a tripod, I've got time to swap them instead of stacking them.
- I know that normally you don't put a CP on a wide angle, but what about the UV? Does that have an impact?
As mentioned, the issue is uneven polarization of the sky, starting at ~24mm (on FF like your 5D). But sometimes the effect isn't bad, and also, sometimes the sky isn't in the shot - a CPL is great for boosting the saturation of fall foliage, removing reflections in waterfalls and the ocean, etc., and in those situations the uneven polarization is less evident, often not even noticeable.
For the CP, I think I would probably go with the B+W 77mm Kaesemann Circular Polarizer MRC Filter, but I'm open to suggestions. Especially if that is overkill, I see that Tiffen has a CP for $38 on B+H, is the extra money worth it?
The B+W Käsemann CPL is excellent (I have them in 77mm and 82mm, and I have the slim ones just in case I need to stack). IMO, putting a cheap filter in front of your L lens isn't wise.
