g1smd - 8:28 pm on Apr 25, 2011 (gmt 0)

- Robots.txt will tell Google which pages cannot be indexed.

It sort of does that, except that Google will continue to list those URLs as URL-only entries in the SERPs. The meta robots noindex tag is a better option, and the canonical tag another improvement yet again. The 301 redirect is often, but not always, the best option.