Picasa

Tried this photo organizing software from Google before, but for some reason it didn't impress me. However, I gave it a second try (Picasa 2) and I like it quite a bit; (especially, if you are like me; used to using Windows Explorer to organize your photos).

• It's very fast to view and organize your pictures (Windows is not custom-made for this).
  
• It can sometimes detect and automatically rotate pictures for you (for those pesky vertical pictures).
  
• Nice simple set of photo editing features.
  
• Collage maker (very cool).
  
• Easy to post online, or for blogs.
  
• Flag "favourite" pictures.
• And it's free.