It seems to me that 3rd party browser toolbars cause more problems than they are worth.
For the vast majority of people, they appear mysteriously, and its assumed that you just have to live with these annoying, space-sapping invaders.
And it seems that every man and his dog, now have browser toolbars to “enhance” (more likely cripple) your browser.
Even Google have a toolbar (but at least its vaguely useful to a small number of people).
Some antivirus software have the ability to block your homepage from being changed. I think they should do something similar to block new toolbars from being installed.
Anyway, in my travels, I have found the alot toolbar to be the most problematic.
In one case, it was intermittently stopping URLs in emails from actually opening the page they were meant to.
Uninstalling alot fixed that problem.
At least most modern browsers now have the ability to easily disable toolbars.