The 7 Deadly Sins of Landing Page Design is a brilliant YouTube webinar with Tim Ash. The seven sins are:

1. Unclear call to action
2. Too many choices overwhelm the visitor
3. Requesting too much visitor info
4. Too much text
5. Not keeping your promises
6. Visual distractions
7. Lack of credibility and trust

Ash is the author of Landing Page Optimization: The Definitive Guide to Testing and Tuning for Conversions (Sybex, 2008). He is also the CEO of SiteTuners.com.