How should I framework my web addresses for both SEO and localization

When I set up a website in several 'languages', how should I set up my web addresses for google and usability?

Let's say my website is ajmalseotips.blogspot.com, and I'm converting into France and Spanish language. What is best for functionality and SEO?

Directory option:

http://www.example.com/sample.html
http://www.example.com/fr/sample.html
http://www.example.com/es/sample.html
Subdomain option:

http://www.example.com/sample.html
http://fr.example.com/sample.html
http://es.example.com/sample.html
Filename option:

http://www.example.com/sample.html
http://www.example.com/sample.fr.html
http://www.example.com/sample.es.html
Accept-Language header:

Or should I basically parse the Accept-Language headlines and produce material server-side to match that header?

Is there another way to do this? If the different terminology editions don't have different web addresses, what do I do about the look for engines? ajmalseotips.blogspot.com