looking 4 eCommerce Script

I am looking for a good updated eCommerce software to setup shop. It should be fully supported and updated software w/ a full range of mods. I also need instant download mod. Before you run off and say OScommerce, is it really any good? I have it setup now, some of these junk options do not even work. The design is crap, the instant download does not work after payment...bla, bla...Do i need to go on? any OScommerce coders/modders out there by chance? Thank-You ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows? (depending on the nature? of the deliverables): a)? For web sites or? other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software? installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform php, unix