Thank god for someone to bring a filter question, rather than 7D Vs 5D2!
Yeah, I was thinking "7D vs 60D vs T3i" or "best _________ lens?" (insert "walk-around", "portrait", "landscape", etc.)
Take an old filter and do a simple test....
Put it on the ground, drop a rock on it. It broke pretty easily, didn't it? Now pick it up, flip it over and gently run your finger over the broken glass... be careful not to cut yourself. Pretty sharp, huh? Well, what do you think will happen when those shards of glass get driven into the front of your lens?
I really wouldn't put too much faith in a thin piece of glass "protecting" from anything very serious.
But it is very satisfying to drop rocks on a cheap filter! They also make really good coasters to protect your nice wood coffee table from those ugly rings, from your cold bottle of beer.
The lens caps and lens hoods that came with my L's do a much better job protecting anyway. I always use them. And I buy and use hoods for any lenses that don't come with them.
I try to be sensible about it of course. So I do have UV filters on hand to use if shooting in a sand storm or something...
But I'd never leave them on all the time. There are just too many times when they can cause issues, a little or a lot depending upon the quality of the filter and very little or more than a little depending upon the exact shooting situations. Besides UV, sometimes I'll use C-Pol or other types of filters, when the filter will enhance an image in some way.
But, sort of ironically, it's even more important to use a lens hood, when using a filter.
B+W are good.... At least the multi-coated ones are, designated as "Pro", "MRC" or "Kaesemann" (the latter in the case of polarizers). B+W also make cheaper uncoated filters, probably good glass but I'd still prefer not to use uncoated or single-coated filters, if I can avoid it.
I don't know what you "just read about too many pros, having their lens front element protected from scratches, by having this piece of glass on it", but that's just the opposite of my experience. Most pros I know will only use filters in specific situations when one is actually called for and would never be so mindless as to just leave a filter on all the time (tho I'm sure there are exceptions!).
One sale of one image made with a lens might pay for replacement of that lens or a repair if it ever became necessary. Since it's what pays the bills and buys more gear, most pros I know want each and every image they take to be the best it can be and think very carefully about things like adding extra layers of glass in front of their lenses. Besides, they insure their lenses against damage or loss. If you're a hobbyist, your gear might already be covered by a homeowner or renters insurance policy, up to some limit of value. Check with your insurer... You might be able to get a rider for additional value, if you wish. A year's coverage might cost cost less than a filter.
I would guess that you're reading an article by a pro who has been hired as a spokesperson for a filter manufacturer... Or perhaps a columnist/pro who is catering to a photo magazine's advertisers, which is pretty common. Some pros even have lines of filters named after them ("Moose", as in Moose Peterson), and quite likely receive royalties on the sales.
Back in the days of film a lot of pros used UV filters more often because a lot of types of film were overly sensitive to the UV range of light. But that's not necessary with modern digital cameras.
When I hire a second shooter to back me up at a job, I always try to remember to check if they have filters on their lenses and if they do I'll ask them to remove them. That saves me considerable image correction work in post processing, fixing the additional flare (ghosting and overall veiling). When I've got 12,000 images to edit in a few days, I'd prefer to avoid any extra work if a bunch of them have flare issues. In some types of lighting there can be no flare... In other lighting it's more serious... And it depends upon the quality of the filter being used as well as whether or not it's multi-coated. Safest thing is to just leave the filter off, unless it's really needed for some reason.