Like Chris said, be careful using CCleaner. It does the trick but it's a registry cleaner. Any reg cleaner can delete files that after you can't boot your computer any more you will wish you had back. I like Spybot S&D still, and have used it for years. I like the tea timer, which blocks alot of carp. It will ask you if it's ok to change things registry wise, or to let things run. It is a memory hog, so on on older computers I tend to steer clear of installing it. Install it, and if it bogs down things too much, just uninstall it.

Browser wise I was an IE guy forever, but firefox is great. I had to use IE at offices all the time due to limitations with people's softwares, so I never really used FF. After installing it at home, I'll never go back, lol.