This lets you quickly swap base outfits and add-ons to those outfits, complete with hotkeys and nifty menus. Everything about this mod just works, and it's pretty simple to get the hang of.
I just can't help but have the Thomas the Tank Engine mod. Even though I expect it, the intro is always funny to me. I grew up watching Thomas so I may be biased as well. Other than that I like to use the child race mod so I can scamper around Skyrim as a young lad killing dragons.