Aardvark Topsites PHP has a ton of features. I'm not going to bore you with all the inane details, but here is a list of the main features.

* Members ranks can be shown on their button.
* New: Stat Buttons, allowing you to customize your buttons and display all kinds of stats on them
* 6 different ranking methods
* Counts unique pageviews, total pageviews, unique hits in, total hits in, unique hits out, and total hits out
* New: Rank daily, weekly, or monthly
* Up/down/neutral arrows
* Customizable categories
* Fully customizeable skins: make your topsites look however you want!
* Simple web-based installer and upgrader
* Multiple pages
* Member login and lost password retrieval
* Seamlessly switches between languages
* Fast, integrated search
* Ad breaks
* Visitors can rate and review members
* Advanced stats and graphs
* Easy to install and maintain
* Powerful admin
* New: Mass mail members
* Best of all, it's completely free!