Recently I upgraded Firefox 3.0 to 3.5, Today I noticed an option in firefox which was probably not there before, I was amazed to know that I can set firefox to remember or not remember the browsing history permanently.
In order to set this option, follow the procedure given below
1. Open Firefox 3.5 and Go to File Menu >> Tools >> Options
2. Click the Privacy tab now
3. As you can see in the image below you can set firefox either to remember browsing history or Never remember history or Use Custom Settings for History
4. Click Ok