Bootstrap was going to ditch Glyphicons (and IE7 support) with 2.2.2[1] but it looks like they're either holding off on that or they changed their mind. I recommend using Font Awesome[2] instead of Glyphicons.

[1] http://blog.getbootstrap.com/2012/11/09/glyphicons-font/

[2] http://fortawesome.github.com/Font-Awesome/

We use fontawesome as well, it makes your site look much nicer.

You can also use http://retinajs.com/ to scale stuff up if you want.

Even better, pack your own custom glyphs from icomoon.io.