The best thing is to have both of them
You can come to my site without registration, look at the content, buy the content you want, then you have instant download links in your email and also instant license.
AND you can also decide to register, so by this way in your account there will be a record of all your orders, download links and license. So you can donwload the content again if something bad happens like a HD crash... Also, it'll be faster to buy the content, because all the info (name, address...) will be already registred so you'll just need to put CC# exp date and that's it
I really thing that's the best way. For those who prefer to not register, that's fine for them. They can come and buy the content instantly; no need to fill out a regisration form.
For those who prefer to keep a track of their orders and to avoid filling in name and address in the check out form, well, they can register
I hope it helps.
Cheers!
