The only part of Google's "power bloc" that I'm involved with (that I know of) is YouTube, where I registered to be able to set preferences and to post comments. My default search tool is Dogpile, which, while it uses Google as one of its search engines, doesn't AFAIK exchange personally identifiable info with Google.
With respect to switching to another a-v, one important point's been overlooked, and that's the level of helpful support here. I don't think any competing product, free or otherwise, offers anywhere near as much support as avast, particularly here in the forums. Sure, there been lots of problems with, say, iYogi, but the almost standard reply to complaints about them is that the user with the problem should have looked for help here first.