On the search subject, I would love to see a couple of extra sections on the dashboard page, one to save favorite searches and one for favorite sellers. One click from the dashboard page and you're there.
A watch list would also be handy, I use all my cash from sales to purchase other cards and it would be nice to have place to save a listing. Maybe throw a red flag up if it changes is price, changes ownership, or if another of the same card is listed.
Just a couple of thoughts from a new guy. My first two months on the site have been great, very easy to navigate and learn the system. Keep up the great work, I'm hooked!
... I would also like to say thanks all of you who have purchased, made offers, and accepted or countered my offers, looking forward to many more.