Filters? Or no Filters? Or just a Lens Hood?

A UV filter doesn't do much. And those are not $900 world class lenses to be protected from all harm. They can take a ding or two. You would have to put a $150 filter on your $98 lens or otherwise just make a poor quality image. Glare and condensation are issues with filters. I say they are not worth the trouble especially on cheaper glass. A polarizer or ND are still very worth it despite degradation. But UV, nah.

Hoods work well enough for me. On that 70-300 you want to use a hood anyways and then the front is well protected. The 70-300 has been my main wildlife lens for more than 2 years. Shot it in the wild in all sorts of horrible weather. Never did use a filter, never did have a problem.

A good quality UV filter will not affect your image quality. Although a lens hood should be used with every lens, its no protection when you're standing around talking to someone and a child decides to touch the front of your lens or a dog decides to lick it. In those instances I'd rather clean a filter than the front element. If you shoot a lot of street pictures be aware of the pollution from diesel trucks and buses as well as regular pollution that can accumulate on the front element of your lens. Again, I'd rather clean a filter than the front element. However, if you want to buy just one filter than by all means buy a circular polarizer for every lens you plan to use outdoors. In the last 40 years I've had good results using B+W, Tiffen and Hoya filters. They are brands I recommend.

Why would a thin piece of glass offer mechanical protection? It's more likely to shatter and scratch the lens coating and still ruin the lens. No filter UV filter will improve the image quality on a digital camera, with film yes, at altitude or in and high UV scenario such as a beach or in snow on a bright Sunny day, but digital is nothing like as sensitive to UV as film. Lenses are tougher than you think. The coating is almost as hard as granite. Actually it is usually a mineral and the coating process put's a 'skin' on the lens, all coated lenses are toughened glass. Chris

UV filters will do nothing to correct haze. Trust me on this. I shoot a lot of photography in the Caribbean were it is hot, humid, and hazy. Haze filters, skylight, UV, or whatever version you want will simply not work. The only way to correct haze is in post production - photoshop, etc. You have to recover the contrast that is reduced by the haze. Even then, it is not perfect, but a lot better result than trying a filter. If you want to use a filter to protect your lens, that is up to you. I generally only have two kinds of filters - a circular polarizer and a handful of different intensity ND filters, as these can do things on the camera that are not possible in post-processing.

Don't worry, everything will be ok. Filter or not filter, I don't want to be phylosophical, but really ther's not unfiltered reality, so put at the end of your lens whatever you want

Well, UV filters are useful for scenics that cover a lot of distance to the horizon, to reduce the more distant haze/"washout" (unless you like that "look"). I also like them for more general reasons, especially in action and manufacturing photography - it's amazing how many small moving objects make a beeline to the lens in such situations. (There's a reason why I only wear prescription safely glasses rather than more stylish "designer" frame glasses or contact lenses.) A low cost UV filter in such situations is _FAR_ cheaper than a scratch/pock marked lens. In the past 40+ years, I gladly pitched dinged UV filters instead of having dinged lenses. Also, I'd rather clean a UV filter than getting my often clumsy fingers that close to a lens element.... In any case if there's concern about condensation, they're easy enough to remove and set aside. Condensation really isn't an issue where I live in the drought stricken desert Southwest. Dust is and blowing sand is often a problem here, and I'd rather clean grit off a UV filter than a lens element. As far as image degradation with UV filters - IMHO that won't be noticed with the vast majority of the images posted to the WWW, and also isn't a problem with the smaller prints I make (unless somebody is going to inspect them with a magnifying glass). Polarizing filters can be used to accentuate clouds and darken the sky, without doing much to the colors. And they can be use to reduce glare off brightly lit/high contrast subjects. In black and white photography, red filters are often used to darken the sky, and others to brighten/darken foliage. There's quite a bit of WWW information on using various filters in B&W photography, so there's no need to go into that here since I suspect you're not into that field. In summary, filters are useful, especially for more specialized work. Hoods are okay in general.