I surf the web in peace and this is my method
1: Firefox - AD Block Plus, NoScript, Ghostery, BetterPrivacy, HTTPS Everywhere, WOT
2: OpenDNS on my router
3: A hosts file addition that makes OS X refuse to connect to the parasites of the Internet (needs to be updated once a month or so)
Firefox + NoScript blocks Javascript which is responsible for pop-unders and MacSheild/Defender and MacKeeper from appearing.
When you need Javascript you enable it by clicking on the NoScript button to "Temporarily Allow All This Page" and Javascript will run. What your doing is establishing trust first and then running your scripts, not running around with your scripts on for every site, reducing the exposure window.
Note: Firefox (like Chrome) is a RAM hog, so if your menu's lock, simply close all open windows and open a new one. It's being fixed in the next version.
One should also be checking the status of their plug-ins routinely here:
https://www.mozilla.com/en-US/plugincheck/
Flash has a new auto-notify that will tell you your Flash is out of date, but only when you use Flash.
#3 is the hardest part and the most risky as it's messing with a system level file, but I've gotten the method down so new users don't have to use the Terminal.
A: Select all and copy all that you see on this page: (bookmark it for later use/updating)
http://winhelp2002.mvps.org/hosts.txt
B: Download the free TextWrangler from BareBones.
C: Open Text Edit and PASTE
D: Delete the line (important!)
127.0.0.1 localhost
E: Do a Find and Replace for ALL instances of
127.0.0.1
change to
0.0.0.0
F: Select All > Copy
G: Open TextWrangler and open File by Name
/etc/hosts
H: Do not touch the original entry! Add some returns to the bottom and PASTE
I: Save the file with your Admin Password.
J: When updating the hosts addition, repeat the same exact steps as above, just replacing the old hosts addition part with the new one. IT's VERY LONG! Do it once a month or when a update rolls out.
Copy this info, save it and surf in peace.
If you can't understand or do the above, don't. I can't help you any further.
Disable everything before changing over to OS X Lion as a precaution.
In short, your resolving the DNS for those hostile websites, ad servers and other crap yourself with 0.0.0.0 or "nothing" so your computer connects to "nothing".
"Nothing" connects, so "nothing" gets downloaded, thus "nothing" gets displayed.
Good Luck and surf in peace. 🙂