In order of importance: Yahoo services I rely on.

1. Flickr
2. Del.icio.us
3. Upcoming (updated)
4. Pipes
5. MyBlogLog (updated)

That's about all I can come up with lately.

What other services do you use from Yahoo? Follow the conversation on Friendfeed

Update: mybloglog is another service I used to use a while back. Thanks to Mike Doeff for the reminder about MBL.