As someone who is always looking for a camera bag, I can tell you that the gear isn't what determines the kind of bag you need so much as your use. The questions you need to answer are:
â€¢ Do you need it to be waterproof or weatherproof?
â€¢ Do you mind if it looks like a camera bag? Does it have to look good? Or do you want it to be more discrete?
â€¢ Do you need to carry other personal gear as well? If so, what else and how much?
â€¢ How long do you need to carry it generally? How much can you carry for this length of time?
â€¢ Whatâ€™s the absolute minimum gear it has to carry? Whatâ€™s the most is needs to carry?
â€¢ Do you need constant access to gear? Or is it just moving your stuff from location to location?
â€¢ Does it need to go on a plane with you? Will you be taking regional planes?
These are all things I figure out before I start looking. Otherwise, thereâ€™s just no end of choices. Sadly, there is no One Bag To Rule Them All.
Re: filters. Donâ€™t know about these in particular, but generally, the more expensive the filter, the better the glass, the better the image. Filters often reduce image quality by adding slight color tints, reducing local or overall image contrast, or physical vignetting, but cheap ones more so than expensive ones. Pay for the better filter if image quality is important to you, is my advice.
D: iPhone 4S, Canon 5DmII, Panasonic DMC-LX3, Fujifilm F30, Canon 30D, Nikon CoolPix 8700 | A: Leica M3, Holga 120N, Contax Tvs, Polaroid Spectra, Canon 50E, Rolleicord, Canon AE-1P
Canon lenses: 16-35L II, 24-70L, 50 1.4, 70-200 2.8L IS, 10-22