Now for a third opinion, get this filter.
I have yet to see anyone, except pixel peepers, show me a protective filter harms a photo. You have a decent lens so is it worth it to you to add a small amount of insurance for $28 bucks?
Of course, being a die hard Canon user, I recommend you get the real Canon hood, also.
Oh, I did not say it was not possible to get and use a crappy filter. The one I suggested for you is a very good filter.
Although I no longer support myself with a camera, I never had a person say to me, "If only you hadn't shot that with a filter on your lens."
That filter is cheap insurance. Even if it only serves to keep the front element clean. And on the same plane, a hood is one of the least used but one of the items that has the biggest effect on your pictures.
Tulip hoods are not needed for a short telephoto prime like the 85mm. They are used on wide angle and zoom lenses mostly. Especially steer clear of the "generic" tulip hoods. They screw into the lens using the filter threads and are easy to misalign, and won't give as good coverage of the lens. They just "look cool".
Get any of the available correct ES65 III hoods. They fit and work well.
As to the protection filter, well IMO you could just save your money. Actually, I do have "protection" filters (mostly B+W and Hoya) for all my lenses. But they stay in my camera bag unless I'm shooting something that actually requires protection, such as out in a sand storm, right at the edge of a race track, paint ball, etc.
I do not leave a protection filter on my lens all the time. I have seen many examples of the problems they can create. Heck, I've had to deal with the issues they caused at times when second shooters used filters without me being aware (I try to remember to check their lenses and ask them to remove them).
If you want a filter for occasional use, or if using it all the time makes you feel better and you don't mind some compromise in image quality, get one.
But, sorry Canon, I'd skip that one. Their filters are decent glass, but not multi-coated and tend to be quite overpriced. I would guess they're outsourced from Kenko or Tiffen. You can get a single coated or uncoated 58mm UV filter from either of them for about $16.
If you must, I'd recommend to get a high quality 58mm UV or Clear multi-coated Hoya Pro 1, HD, HD2 or HMC; or a B+W Pro MRC or Pro MRC Nano; or a Marumi multi-coated (EXUS, I think); or a Heliopan SH-PMC. Those are all high quality and multi-coated, that I'm familiar with. I'm sure there are some other good quality, multi-coated.
But keep in mind that any filter has some effect on your images. It can be very little with a quality filter under good conditions, or it can be a lot when there is strong specular light striking it, and a thin piece of glass really doesn't offer much physical protection. The nice, deep hood offers more physical protection than any filter ever could. In fact, when using a filter it's even more important to use the lens hood, to protect filter and lens from both oblique light and hard knocks.