My short website questions (espec for Agaric)

Each question has two potential answers: the answer, or "no one here knows, Stephen should go figure it out." Let me know when it's time for me to do research and when I should listen...

* version 4.6 or 4.7?
* spam resistance... having users explain why they're there, filtering comments, trust factors for users
* What's the best forum? How do we create a sense of place, where people can link into sections of the forum (or do we create more than one forum?) for very specific sub-topics?
* How do I create a mini-landing page describing a part of the forum? Like: http://www.spaceshare.com/community/?q=forum/83
but I want it to look like:
http://www.spaceshare.com/community/?q=node/148

* What's your approach to templating?
* What's the best way to have a complex menu that changes depending on people's "trail"? (The old SpaceShare site does that... a festival planner might see the part of the greening guide about planning, even though that is centered in the
* Wouldn't it kick-ass to have a context-sensitive drop-down menu? Something like a site map, you mouseover "festival planner", and the menus (someplace else) drop down a limited selection based on what's appropriate for a festival planner from the menus.
* We're going to have 1 user table. Maybe the "intranet" will simply be an organic group? Any thoughts on the complex theming and access permissions? I'm guessing that the access controls will all be centralized, the same across multiple site...
* CiviCRM, CiviMail:
1) how would I get started
2) how do these really work? It's a very big jump to get rid of my existing system and switch over. I'd like re-explore just how sane this is going to be. Does CiviMail integrate emails coming in with (emails going and and other data about a client.)?