I agree that they are good for interlinking, but if you have all the different "archives" enabled you end up with a ton of dupe content all over the place and a lot of extra interlinking that isn't really necessary. Additionally, if you are using something to show related posts, your site will be interlinked by relevance anyway. I don't think that all the archives are bad altogether, I just think most of it is un-necessary and redundant. One thing that I have had happen in the past when I just started with wordpress is to have a tag or category page rank instead of the actual post that the content came from, which is irritating to say the least. What I usually do with Robots meta plugin is to disable every archive except one (usually the tag archive) and set it to no-index, follow. That way it still interlinks but doesn't hijack my serps (seems to have worked so far in this respect anyway)