I run the http://minecraft-server-list.com/ and in my next update that I am working on, will include more Category items, so you can be even more specfic with your server/plugin setup.
I am thinking the Gametype should get expanded a little to include things like: Tekkit, Gameplay (skyblock, hunger games, PLEASE GIVE ME MORE SUGGESTIONS HERE)
I'v also noticed a big amount of Tekkit servers, so will add that.
And maybe some list of popular plugins that can show the way of the server (mcmmo, factions, more?)
Last, many have a Dynmap (livemap), so I will try make an iframe solution, so you can show your Livemap dirctly on the Server list.
What I am asking here from you guys:: Please give me your suggestions - what do you want to be able to add as options on the Server List?