Currently, I only have a Radeon 9600 with one DVI port, one VGA port (currently being used by my current LCD monitor) and an S-Video port. In the future (near I hope) I'm going to upgrade to a new system with a Geforce 8800 GTS, which has two DVI ports. The new monitor I have only has a Dsub connector so I'm unsure how I am going to get this all to work if it is even realistic.
It's realistic. All you need is something that every video card comes with and that is a DVI to VGA adapter. You may actually have a few of these laying around from your 9600 card but any new card you buy will have them. The DVI/VGA adapter allows you to connect a dvi video card to a monitor that only has a D-sub connector like the monitor you just purchased. You simply just need to 1) attach the adapter on the end of the DVI cable 2) connect the vga/d-sub end to your monitor and 3) connect the DVI end to your video card. Simple. As for your 360 just connect it to your HDMI connector which i'm sure you've figured out by now.