Here's a big <button>:

It's pretty. When clicked, it opens the file dialog of a hidden <input type="file">, programmatically. Hot!

( Tested in Chrome, Safari 5.1.1, FF 11.0a1, Opera 11.60 )

In WebKit, you can also [ easily ] style an <input type="file"> using ::before:

You can do the same in other browsers but it's a bit more involved.