Curriculum

I believe parents can educate their children on a shoestring budget and I list many free sites under "Online Resources". But for families who have a bigger budget and looking for quality materials, here is a list for you:

Rainbow Resource has curriculum counselors that you can speak with for free.
Used Homeschooling Curriculum - yahoo group where you can pretty much find anything for a great price

Full Curriculum
Abeka - online version is more expensive, but terrific all-around program
K12.com - Language arts, math, etc. is about $300 each
Time 4 Learning - affordable online curriculum
Study Island - Students can work through the web-based program at their own pace, or teachers can guide students through the program. $60
Ambleside Online - free Charlotte Mason curriculum preK-12
Classical Conversations - Christian community program

Language Arts
Sing, Spell, Read, & Write - wonderful program for younger students $250
BraveWriter - online course
Excellence in Writing - parent may need to learn to teach the program
Voyages in English - teacher's guide is expensive

History
Story of the World
Ancient Egypt resources
History of US
Teaching Company - wait for 70% off sales
Books by G.A. Henty
Connect The Thoughts 
Liberty Kids - affordable animated TV series for ages 5-10
CA history - Beautiful Feet

Science
Science in a Nutshell - lessons, lab sheets, and all materials
Basher Books - Easy to read books on all kinds of topics (Physics, Chemistry, Astronomy).  Subject level as high as middle school, but accessible to 8 years and up.

Art/Music
Discovering Great Artists by Mary Ann Kohl
You Can Draw in 30 Days by Mark Kistler
Simply Music

Preschool
Young at Art by Susan Striker

Math
Singapore Math - actually quite affordable with each textbook, workbook about $10
Saxon Math - can also purchase placement tests, curriculum about $40
Right Start Math
Math U See
Life of Fred - good for "big picture" learners
Dreambox - From $13/month, iPad app, too
Danica McKellar books - "Math Doesn't Suck", etc. - good for middle school girls
McRuffy Math - $50