The very best I think, and my personal favourite is the Waka Waka range of products,
http://waka-waka.com/ one of the biggest reasons I love is this company literally gives one to needy countries every single time they sell one. Helping provide power to 3rd world countries! The products themselves are also fantastic and can charge your cellphone several times before needing charging again, then you just leave it out in the sun and it charges via solar panel!
