Like others have said:
1] better search options, and then better fine-tuning of those results
2] series order would be WONDERFUL [again I guess that would be techically under 'search', but still, for series-junkies like me, it would be a GREAT addition
And I would like to know if something is eligible for a coupon/code without having to start the check-out process each time. It's not a deal-breaker for me, but it sure would be a helpful feature.