<p>I'd like to answer 2 and 3, even though I took the AP class (though I seriously feel like I learned just basics in my class and gathered the rest from my review book). I got Barrons (2008 version as well) and thought it did an average-to-good job. It may help to know stuff from the news, but it's not necessary as long as you memorize some specific examples for some of the topics. I did not read or see An Inconvenient Truth/Silent Spring.
I feel as if Barrons did leave out a lot of specific factoids that my textbook covered (percentages for random things, etc.) but many can be figured out from common sense.
For the invasive species question during the test this year, I got my information from a video we watched in class, and Barrons didn't cover that. I think the internet would, though. If you're going to study, definitely do more than memorize a review book--go on the internet (teachers have review sites and vocabulary lists up, though they're not always well-written or AP style), do past free-response questions, and memorize laws/famous international meetings and explore case studies such as events and names of key locations (different areas that have been affected by humans, nuclear waste accident sites, modern geographic happenings, countries that contain vast reserves of oil, etc). Off of the free-response questions from past years that the official CB site has, think of some things that haven't shown up on the FR yet that could, and probe into those subjects as much as possible.</p>
<p>I've heard really good stuff about REA as a test prep company, but it's not the most famous brand, and I've never tried it myself.
No matter which book you get, if it has a CD-ROM version with extra practice tests on it for like three bucks more, get that version.
Alternatively, if you're self-studying Env. Sci. even though your school offers the class, see if you can check out the textbook from the library for the year anyway.</p>