Financial sites:
Kiplinger.com
Wall Street City

Editing/Reference/Web:
Freeality.com
Your Dictionary.com
Merriam-Webster Online
Hot Wired Outtakes
The Slot (A Spot for Copy Editors)
Useit.com
Dictionary.com
Common Errors in English

And for fun. . .
The Onion.com
Borowitz Report.com