I like any gametype except maybe BunnyTracks and sometimes Instagib in UT99.  I'd even play all weapons in UT99.  We used to have many game types on one server until we decided to split it up ( http://www.dfbgaming.com/Thread6485.html ).  One server was sniper and the second server was MH, Binslayer, Instagib and EO.  We took down the second server awhile ago because no one was playing on it after we went to UT3.

If this is about getting the server popular- the best way to have a server popular IMO is to keep the server simple.  The least amount of game types, mutator count etc... the better.  The majority of people wont get bored by playing the same stuff over and over again.  When a player comes to a sniper server and likes it they want to come back to a sniper server.  Not many people like sniper, binslayer, instagib, CTF, JailBreak, TDM, DM etc... all at the same time.  Ultimately it's up to you guys since it's your server though.