Branding, in general, is hype. (Ira) Tiffen, Hoya, B + W. (even Nikon and Canon, Pentax, Minolta, Chromofilter, Cokin (Cokinlight), Asanuma, Tamron, Toshiba, etc.); are top-level; Quantaray, Kenko, Kalt, Sunpak, Lynncrest, Spectrastar, Rolev, Vivitar, Coastar, Massa, Kalimar, Spiralite, etc are second tier brands - brands who sometimes make filters for the top tier as well as their own brands -- so the brand doesn't mean what people here want to think it means
Don't be fooled by fanboys, which is what brand followers tend to be - get what you need, want
I always use a UV filter or a daylight filter on all cameras I use and suggest to students to do the same in my classes - it is tyhe most effective protection you can buy when the lens cap is off and in general any new filter will be clear.
Look into graduated neutral density AND graduated colors (to darken the sky, etc.); cross filters (they basically look as if there is a screen in the filter and they change pinpoint light sources into 4, 6, 8 pointed stares of light, etc.); regular ND, Circular Polarizing filters (regular polarizing filters affect your autofocus and metering)
avoid triangle, etc prismatic filters with digital (they cause so much rainbow effects that your pictures are nearly indistinguishable - works with film but not digital)
Look into diopters (Macro +1, +2, +10) if you are wanting to take macro pics with a fixed prime, hand held, in the field
Look at Cokin flat filters with holder if you really really want to get creative
Most of all PLAY with the filters and see what they do
NOTE: you can buy filters used - in my small area we have two stores that buy and sell cameras and outfits and sometimes they sell filters as low as $1 each, often $3 each - great for testing / learning on (for my classes I bring in a box of 100 or so various filters and let the students play with different ones - I do warn them that zoom lenses should not have more than 1 filter at a time while primes having fewer elements can use 2 to 3 with acceptable results)
