Well, I've got some pretty neat water for my RTS. Two single planes, one is opaque and symbolizes "deep water". The other one is translucent, is a couple scale "feet" above the other and is "shallow water". Here are some examples below.
The only thing I'm missing for realism is a way to animate waves or at least give water somewhat of a current (for rivers, etc.). I need something simple, yet effective. I'm hoping for perhaps a way to animate the texture itself. With Blender3d is there any way to do this?
Simply using a water scene node will animate the waves for you, or you can do that yourself by having the water as a grid of vertices and using trig values to change the height of the vertices which works quite nicely. You could also do the waves in a vertex or pixel shader as well but that gets a bit more complicated.
hmm.. water is the special effects department's responsibility!
will it use realtime reflections, or simple reflection maps? will it be shader based? will it even require a mesh, and if so, how detailed will it need to be? do you need to create a sea bed under the water?
you need a decision on what kind of technology will be used before you can make art for it.