Some who are running Vista - 64 bit version may now know that Vista 64 ships with two versions of Internet Explorer.  On my system they are located:

"C:\Program Files (x86)\Internet Explorer\iexplore.exe" - 32 bit

"C:\Program Files\Internet Explorer\iexplore.exe" - 64 bit

I use the 64 bit version most of the time as it is faster to load and opperate along with safer browsing.  It is safer since it does not allow active-x plugins to run such as Flash and some viruses.  When I need to have active-x features, I boot the 32 bit version.  

On my system, I have an icon for each on the Quick Launch Bar although I do use different icones for each to easily see which is which.