Mike -
In regards to keeping some Skagit wild coho or any other wild salmonids for that matter my approach has been to balance my desire for fresh fish with the health of the resource I'm fishing on and the value of individual fish in the population to the fishing experience. Fish (this discussion should apply to more than just salmon) are both a healthy and tasty food source. I also believe that the retention of some fish is an important part of the fishing experience.
In practice I harvest wild fish that come from robust populations (recent examples would last year's pinks, this year Lake Washington sockeye, Puget Sound ling Cod, etc). In stocks where there are marked hatchery fish as well as wild fish I try to focus my harvest on those marked fish and only keep unmarked fish that are potentially mortally injuried (assuming it is legal to do so). There is an unmarked coho in my frig right now that will tonight's dinner.
Examples of cases where I feel that individual fish have high value to the fishing expereince and I have opted to release all of the them include wild steelhead, sea-run cutthroat, Dollies, stream resident trout, large bass, etc.
Please note the above is based on my values alone. The more that one fishes on some of these populations the more important it is the release all those caught - reserve if you will you impacts to the hooking mortality and not compound ones impacts by keeping some additional fish. In the examples above I geneally fish often enough and with enough success that my CnR mortality on those fish over the years is likely as high as most angler's harvest of those species. I recognize that and I have opted not to harvest those fish. The alternative to limit my own impacts on the resource would be to fish less. I should not that 99% of the fishing I do is with barbless hooks regardless of the fishery and most of it with flies.
To be fair I should mention that with the last of the kids out of the house (off to college) it doesn't take a lot of fish to satisfiy the wife and my needs.
In short Mike it is up to each of us to develop a fishing ethic that we are comfortable with and that is within the biologically and social limits of the resource that we all enjoy so much.
tight lines
S malma