What e-commerce solution should I use? Are there any good ones?

I was quite happy with WP e-Commerce (the one from Getshopped), but unfortunelately it conflicts with Simply Exclude, and there is no solution in sight. As I use WP as a CMS I need to be able to exclude categories from the front page.

Our main business is not selling stuff, we’re a non-profit, but we have some books, t-shirts and buttons that we sell. That means I want something simple that can be integrated into our site rather easily. I’ve tried several solutions, but they are all rather bad or doesn’t have the feature I need. I need to be able to do the following:

– manual shipping rates based on weight
– manual payment (we don’t use PayPal, we just bill our customer with the shipment)
– actual localization (not via some shitty other multi-language plugin ie. I want a .po-file)
– truly free (as in beer at least), ie. no branding of the plugin on my site

Do anyone have any suggestions? Any good experiences? It seems that my feature request list rules out nearly every e-commerce plugin there is… 🙁