How to keep released binaries under version control

I'm not sure you'd call them a serious act, but MySpace are pretty poor on this front: See http://highscalability.com/blog/2011/3/25/did-the-microsoft-stack-kill-myspace.html.

Tags and branches aren't mutual, you can (and IMO usually should) use them both. Tags are there to mark milestones in development. E.g. you open a branch for version 1.2 of your product, and you mark v1.2 Beta, RC1, RC2, Final (and then, if needed, SP1 etc.) with tags on that same branch.

I personally prefer Method 2 as the default approach (although I try to avoid multiple levels of branches, to keep life as simple as possible). Method 1 is just not going to work in real life - tags aren't enough, you need branches. And method 3 is inflexible in that it has only a single stable version at all time, so (unless you combine it with Method 2), you can't maintain multiple (latest and older) versions in parallel. This is required for almost all projects in real life - while you are working on version 2, you should still be able to publish patches / upgrades for v1.9, and often even earlier versions. A lot depends on the type of application of course. We develop a web app, so there is only one production version at any given point in time, still we often juggle with 3 different versions (one in production, one is in UAT getting ready for deployment, one is the latest version on the trunk). It can get way more complex for a desktop/client app with multiple older versions being used - and maintained - in parallel.