People are too lazy to fill out alot of question before purchase something. I re-design my checkout page from 4 pages down to 2 pages. The first page ask customer's shipping, billing address and credit card info. Second page, it's confirm the purchase. You may think the second page is not necessary. But i don't want customer any reason to ask for charge back or return.

Why need registration? You just need the shipping,billing and credit card info to process the order. If customer want further information(newsletter, catalog), you can have separte page to do this.