Suggestions for Internet Shopping Cart Needed

I’m looking for a good shopping cart program for internet purchases. Since I believe that many Dopers have internet businesses, I was hoping for some recommendations. Sadly, my Google-fu is currently not the best.

Also, thanks for everyone who gave me advice about laptops (and who posted in other people’s threads, I checked them out too). I ended up with a super sweet Christmas present that is slowly taking over my life (not that that’s a bad thing).