There is nothing more depressing than a vast office space lit with recessed egg-crate light fixtures. The ceiling is dark, and there is harsh contrast where the fixtures shine down on you. The best lighting you can have for your open office space is direct/indirect fixtures.
What this means is that a small percentage of the light reaches your desk directly from the fixture - down light. But the bulk of the light reaches your desk indirectly - up light bouncing off a light colored ceiling. This scatters the light, removes shadows and harshness, and gives the room a bright appearance because the ceiling surface is brightly illuminated.
There are many of this type of fixturs on the market. Finelite makes a range of direct/indirect fixtures in a range of costs and is a good place to start.