Re: No guilt at all
I will disable my (fairly fierce) adblocking where experiment and experience show that a site has what I regard as an acceptable advertising policy. Fortunately, El Reg falls into that category. Adblock Plus and Ghostery are disabled here, and I value the content I get to see as a result. I have to add that this is one of only four websites where I have chosen to do this.
By and large, when faced with a decision on content vs adbombing, content usually loses. I have deleted (decluttered?) a lot of bookmarks recently, for sites I will no longer bother to visit, and you know what? I am no worse off, AND I seem to have a lot more time to do productive work.
My personal fallback is to install two (unsynchronised) browsers, one fully adblocked, and the other unprotected. If I really want to visit a less-than-favoured website, I will simply use the unprotected browser. Doesn’t happen often, though.
Do I feel guilty? Hell no.