Matt - I use Hoya HMC filters on my L lenses. The HMC stands for multi-coated, which reduces flare and glare. These filters are just about in your price range, and I would not recommend anything less, as a lens, like a chain, is only as strong as it's weakest link. And filters have saved my a$$ a couple times, as I shoot weddings and have to do VERY fast lens changes. Sometimes I get in such a hurry that I will throw a lens in my bag without putting the cap on. But worst case scenario here is that I have to replace a $35 filter not a $1200 lens. I also shoot at the beach a lot, which can be tough on glass, so I like knowing I have filters on here as well.