Best Free Browser Protection Utility

There's a scumware plague at the moment. All it takes is a visit to a pushy web site or a "loaded" shareware install and next minute your Internet Explorer homepage has been changed, your default search setting altered, unwanted ads pop up on your screen and worse.

[1] http://www.sandboxie.com Free for personal use, Win2K and later, 310KB
[2] http://www.javacoolsoftware.com/spywareblaster.html Freeware, all Windows version, 2.5MB
[3] http://www.javacoolsoftware.com/spywareguard.html Freeware, All Windows versions, 913KB

These are the freewares that guard your browsers.