You should try BitDefender Traffic Light.
I use it alongside WOT, but WOT can be misused by "communities".
You could also try LinkExtend which uses databases from a number of good link scanners like Norton Safe Web, Google Safe Browsing, PCTools Browser Defender, etc.
My advice, stick to 1 or 2. Too many addons will cause your browser to consume excessive memory and lead to a laggy performance.
If you want additional security, use a Sandboxing software.