Visiontek is a very good brand. From what I remember, support was excellent. I had a Visiontek GeForce Ti4200 way back. I had to RMA it and the whole process was quick and easy.
The specs say the
ATI HD 2600 Pro has full support for DirectX 10 so it should run under Vista just fine. It also needs at least a 400W power supply.
As for the drivers, just use the one's available directly from the ATI website.