Dream This Day - http://www.dreamthisday.com/
Database of inspirational quotes and also lists a daily quote. Mostly focused on happiness.
Living Life Fully - http://www.livinglifefully.com/
Variety of different quotes that relate to every day life. The quotations can be searched.
Thoughts for the Day - http://www.markamoment.com/
Many different quotes for each day. Most of the quotations also come with a picture and users can submit their own entries.