I like the existing smilies because they're nostalgic. They remind me of the ol' UBB days. +1 for the suggestion of adding a 2x version of these designs to core.

Now, I *also* like the new smilies on WordPress.com. They're HiDPI, clean, modern... all that fun stuff. So, seeing as they're coming from WordPress.com, why not add them as a feature to Jetpack?

After all, isn't Jetpack intended to pull in the cool WordPress.com stuff for self-hosted users?