At ZURB they have developed a super awesome buttons with css3 & rgba.
It’s a simple button made possible by a transparent PNG overlay (for the gradient), border, border-radius, box-shadow, and text-shadow. See following image and even dont forget to checkout demo, its very attractive.
Link – http://www.zurb.com/article/266/super-awesome-buttons-with-css3-and-rgba
Demo – http://www.zurb.com/blog_uploads/0000/0617/buttons-03.html