TheBigK - 4:41 am on Dec 4, 2012 (gmt 0)
Alright, here's 'latest' from Google's John Mu on the same discussion I had initiated. Who should I really trust? I'm turning into a paranoid!
The number of crawl errors on your site generally doesn't affect the rest of your site's crawling, indexing, or ranking. It's completely normal for a site to have URLs that are invalid and which return 404 (or 410, etc). That wouldn't be something which we would count against a site -- on the contrary, it's something which tells us that the site is configured correctly.
For more information about 404's in particular, I'd also check out our blog post at [googlewebmastercentral.blogspot.com...]
When it comes to marking crawl errors as "fixed" in Webmaster Tools, this is something which is not used for the rest of our crawling / indexing systems, it's only used to simplify things in your UI. We try to bubble up more important crawl errors (such as pages that recently existed), so if you're not seeing any important URLs there (such as some that you thought were valid URLs), then I wouldn't worry about those crawl errors.
So in essense - he's suggesting that the broken links that originate and point to your own domain are 'fine'. WTF?