I've got a newbie question should I install W3 Total Cache before my plugins & theme or after there installed.
After. And you should set it after you have made all of the changes and edits that you are going to make, or disable it as you are making them.
Quick answer, I don't think it really matters. W3 Total Cache senses when the cache goes stale if you add other plugins, change theme, etc. It will let you know when to clear the cache.
I can just wait until I get the majority of my plugins installed. Here's what I've picked for my plugins & theme some of the plugins are for hiding my affiliate links & keywords. Theme: Atahualpa 3.5.3 W3 Total Cache ShareThis Google XML Sitemaps GoCodes Exploit Scanner CPA Redirector AWeber Web Form All In One SEO Akismet
How much traffic does your site receive? Unless you're receiving thousands of pageviews a day cache plugins are unlikely to make much of a difference.
It's not just a digg effect the plugin takes a load off my hosts server & loads a hell of a lot faster using that plugin.