So despite Sirrith's excellent point of...
Sirrith wrote in post #15806734
So I don't see the point of turning this into another ridiculous thread on filters vs no filters.
...we're heading down the usual road .
Let's look at it this way: anything you put in front of your lens is almost certainly going to have some negative impact in some circumstances. The question is: are you willing to accept the potential problems, given the benefits of protecting the front element?
Roger Cicala at LensRentals has previously made the point about the low costs of replacing the front element of most lenses - such that it doesn't make economic sense to use a UV filter (especially given the potential problems it may cause). However, I suspect that most people would find it cheaper/quicker to replace a £50-£100 filter than send a lens off for repair.
I've tested lenses with/without the Hoya HD UV filters, and found no discernible metering difference or image quality (even when pixel peeping) in the tests I've conducted. In terms of real world shooting, it's entirely possible there might be reduced contrast, increased flare etc. - but I can't recall a shot where I've suspected problems with the filter. Obviously, different shooters will experience different scenarios, and you must make the judgement yourself.
Having not been aware of problems, and having had small people manage to poke the end of a lens with a stick (despite the presence of a hood), on balance, I use (hopefully decent quality) UV filters*. Different usage scenarios may demand a different choice.
* Except when I'm shooting auroras, mounting other filters on the end, doing landscape work on a tripod etc. (i.e. it's all about scenarios)