[dec0dedab0de]

My biggest issue is ending up with search results when I forget to use http:// for a tld that is only accessible from the network I am using.

Other than that, I don't like the idea of automatically sending my browser history to my search provider. To that end, I also immediately turn off phishing protection on all new installs.

[padenot]

You should really look into how phishing protection works in Firefox [1], it's not implemented in a naive way (i.e. does not send the url to a third party), and does not compromise your privacy.

[1]: http://blog.sidstamm.com/2012/02/malware-and-phishing-protec...