The new version of Internet Explorer (version 7) has a simpler and more effective way to delete all references to the websites you've looked at from prying eyes (like your wife's or co-workers') who are using the same computer.

Here's how it works:

Click on Tools, then on Internet Options.

Then, in the General Folder, under Browsing History, click on "Delete...".  In the new window that will then open, click on "Delete All".

In the next window that then opens, be sure to check "Also delete files and settings stored by Add-Ons".

This checkbox feature (new in IE 7) will, for the first time, enable you to delete all the subjects you've previously typed into Yahoo or Google (which used to appear when someone started to type in their Search windows). So your wife will no longer see that you did a search for "CityI'mVisting Escorts", etc.

Then click on "Yes".  

[Yes!]

Being careful to do this, habitually, after each potentially-questionable internet session may save you a lot of embarassment and explaining(and possibly, divorce settlement).  

If you do not have IE 7 (and are using a previous IE version), click on Tools/Internet Options/Windows Update and follow Microsoft's easy-to-follow instructions. (The download takes a little time, but is free)

Users of other browsers (Mac, Firefox, Opera, et. al.): do you have parallel suggestions to share?

Computer professionals: have I missed or mis-stated anything here?

Good damn info!

Even in IE7, clearing history etc. does NOT erase information on the DAT files... along with history of other program file DAT files you may have on your machine... if you are in this hobby, the small sum of from 20-30 bucks is well worth the investment to cover things...
I have used program on link for years, it totally wipes out DAT files by replacing info in them with all zeros.... there are others out there, so depending upon individual taste and budget take the plunge and you will be thankful for it...

The only 100% secure method is to rent a virtual server for less than 100 bucks a month.

You log into a virtual desktop and browse all you want.  Just close the window when you hear the garage door.  

For additional security make it an offshore company.

Theres a program out there called ccleaner, which you can find at ccleaner.com.  This program is free and should take care of all your needs.