Have you played around with Agoracart,
http://www.agoracart.com? I was using that before I went with the "package deal" for my merchant account. The agoracart software is very configurable and there is a support forum where other users can help you tweak something just how you want it. I liked that shopping cart software a lot more than the one I'm using now, and the only reason I'm sticking with the one I bought was because of the tech support that was part of the package.
My pet peeve with orders is people who order with a hotmail or yahoo email address, and then I can never contact them because my emails get bounced, their account is "over-quota", or any number of other free email related problems. It gets very frustrating when people using these types of email services never get my replies and they keep emailing me stuff like: "Dude, I placed an order and I never heard anything from you. Why won't you answer me????"