I use HNES (Hacker News Extension Suite) and it's awesome.
Here's the GitHub link: https://github.com/etcet/HNES
etcet is awesome about contributions, I added a big feature and he merged my pull request within hours.
On top of making HN look way-more-awesomer, it also adds features like comment collapsing (best thing ever), inline comment reply, and more.
If you're a Hacker News user on Chrome, definitely check it out.