Hello all ;D
I have a VServer with 2GB Ram. the mcserver is for me allone. But I ask me, is the ram enough or brought the more ?
Generally MCServer needs 128 megs of ram plus about 80 per player.
So your server should be enough for 25 people

Actually a few more players than that. My server, which currently has 128MB of RAM, has managed to handle at least 6 players.