How can I replace HTC Sense? I saw not using HTC Sense as a power-saving tip on another question, but I just wanted to know what the easiest way to replace HTC Sense is and what it requires me to do?

Do I lose all my widgets too or will it mostly change the way my Home screen looks?

Edit: I don't need HTC Sense to disappear completely from my phone or need to root it. I'm just curious how I would go about replacing HTC Sense with another application launcher.
To replace HTC Sense completely you will have to root your phone and replace the ROM completely. Please see this post for more information: How do I root my Android device?

If on the other hand you're looking at replacing your homescreen/launcher then there are plenty of options.


LauncherPro
ADW.Launcher 
HelixLauncher
plenty more...


I personally have LauncherPro and have upgraded to the Plus version. The Plus version has 90% of the widgets Sense UI has but is in my opinion far quicker, more stable and has way more features.

NB: I don't believe any of these Launchers allow you to utilise the widgets from Sense UI.

EDIT: Just to answer your comment. LauncherPro is an app you can download and install from the Android Market. Once installed clicking the Home button will prompt you to select which launcher you'd like to use (either LauncherPro or Sense UI). All you would do from there is check the "Default" checkbox and select LauncherPro.