Well the zombies wouldn't stand a chance against thous wizards, and if the killing floor guys got regular ammo drops they would probably do fine, until they had to fight a yeti, or actually Kan would probably do them in, if they managed to get past the battle mages and giant trolls with grenade launchers. Oh, I thought this was about who would win in a fight...
In that case go magicka, that game can be a hell of a lot of fun to play solo, but I only play killing floor with friends. Though if you have friends to play with, i recommend killing floor. Magicka is still a little rough around the edges when it comes to multilayer.