As a further question. Would it be best to auto redirect or give a visitor a choice as to what layout they view
This is the big question... and one with no clear answer:
http://www.netmagazine.com/features/big … t-strategy
Here's a good explanation of adaptive-fluid-responsive layouts:
http://www.onextrapixel.com/2012/04/23/ … a-queries/
For the site I'm working on now, customer polling led to the conclusion that a fully responsive site was the way to go. Plus, it's easier on the site owner, who will need to make weekly and monthly updates. Everything in one place rather than 2 different site versions. But this is a small site – only 4 pages, no lengthy articles or 10,000+ product store – so it's well-suited to the responsive layout.
For larger, more complex sites, I think I would do what Eric mentioned. But, it really depends on the type of site and the potential users.
Dive in, Prism! I'll need to pick your brain about some PHP for auto-sizing images when I get a bit further along with this.