Has both a general introduction to terms like power of attorney and the difference between bypass and QTIP trusts, and more complex planning features like a net worth calculator and an Estate Tax Exposure meter. Ask SmartMoney, a Q&A; section, is also worth a read for information on topics like "Help! My son married a gold-digger!" and "Hands off my inheritance." Overall a comprehensive and easy to understand site with additional information on topics such as how to leave your IRA to a charity.
BEST: Separate dedicated section explores life insurance in-depth that other sites miss: a glossary, how to save, and how much you need.
WORST: Great, easy to read overview, but for more depth on individual topics you'll have to go elsewhere.