Voodoo Extreme -- DirectX or OpenGL? The age old Question....

Personally I prefer OpenGL because it's not tied to the Windows operating system, but D3D8 has come a long way since D3D7 and if Microsoft continues this trend, D3D9 will be very nice. I just wish they had a real specification instead of the current fuzzy documentation. D3D8 also still has some issues I can't believe they didn't notice or care about, but it is largely usable. Changes to OpenGL (unlike with D3D) have to be thought through more carefully as breaking compatibility is not a viable option for OpenGL's Architectural Review Board (ARB), so it usually takes them longer to implement features into the core API. I tend to prefer the extension mechanism OpenGL uses over the D3D approach of changing the API drastically. It allows IHVs (independent hardware vendors, e.g. ATI or NVIDIA) to fully expose their functionality and provides a test bed for usability and feasibility before it finds its way into the core API. But this can create issues with intellectual property as seen with the OpenGL equivalent of vertex shaders.

As you can see I'm largely torn when it comes to my API of choice on Windows. But in the end it's not the API you choose that will determine how good or bad your game looks - it's what you do with it ;-)