2. Make the 'search radius' logarithmic.
3. On the map, why are multi-item pins orange vs. green? It's unclear and confusing.
4. Remember my location, search radius using cookies/session.
5. When I click on a pin, highlight the corresponding item in the list pane on the left.
6. Why not show me both (the eBay link + item pic) when I click on a pin or when I hover on the list pane on the left?
7. Can I have a feature to see 'buy it now' items only?
Overall, great work. Keep it up :)