tedster - 3:55 pm on Jan 19, 2012 (gmt 0) [edited by: tedster at 5:48 pm (utc) on Jan 19, 2012]
I would definitely go with HTML5. Even more, for any site being built today, I'd make sure the code is smartphone friendly. I wouldn't worry about feature phones too much, unless you know that the feature phone demographic is squarely within your site's target market.
[edited by: tedster at 5:48 pm (utc) on Jan 19, 2012]