App launcher:
Launchy (Fast, Skinnable)
Alternate Font Renderers: (for the nice smooth screen text)
Gdipp
MacType
Better Video thumbnails on explorer:
Media Preview (also allows the removal of that fugly reel overlay)
Icaros (provide Windows Explorer thumbnails, for essentially any video media format supported by FFmpeg)
PDF Viewer:
Sumatra PDF (crazy fast start-up, ultra light, remembers the last page read for each file)
Personalization:
Aura (change window color based on wallpaper or active app icon)
Educational:
Anki (Flash card app. I use this to review kanji, works awesome)
Misc:
Anime Checker (verify the integrity of your files. Hard to explain, just view the website for more info)