I always leave javascript disabled for all but a 
very few sites.  Pop-ups have become increasing 
aggressive and obnoxious...  There are even some 
that install programs and automatically click 
the "install" and "always trust content from this 
company" buttons so you don't even know it's 
being installed, and once that happens they can 
load up your computer you with all sorts of 
spyware without ever having to ask your 
permission again.  Pure evil! -_-

AdAware is a good program, but I have found that 
Spybot find quite a few things that AdAware 
misses.  It's downloadable at 
http://security.kolla.de/ (though the site is 
down at the moment because they've gotten a lot 
of press lately).