The river walking zombies is Land of the Dead with Dennis Hopper and John Leguizamo (sp?). It's ok, but only if you like most any zombie movie.
The one with Ving Rhames where they dock on an island at the end is the 2004 Dawn of the Dead. That one is ok.
The one where people are on the island with a "controlled" zombie population is, Survival of the Dead. I think someone mentioned that already. It's terrible. I do not recommend. That's sort of a follow up to Diary of the Dead, which uses the first-person thing where they hold a camcorder. I thought it was lame.