I think I have finally figured out why I have a 20 to 30 second delay when using FF 3.5.5 with Mint 8, Ubuntu 9.10 and PCLinuxOS. All are up to date also.
I always clear all personal data when closing FF. Been doing that for about 6 six years.
When I open the browser again, it appears FF 3.5.5 wants you to keep all data, at least History and Cookies so it takes time to re-connect. Have not narrowed that down yet.
It has been very repeatable in testing.
I suspect I am about the only one this is happening to.
I checked in the Mozilla forums and no response to my question at all.

Rich

Hi, Rich~

I have the same issue, although I do not delete data. I also have some stability problems, as well; i.e. buttons and links on web pages stop working- I have to close and restart Firefox. I think the last update broke something, as it worked perfectly before.

Cheers