Questions for SLI and Crossfire users

Folks,

I'm within striking distance of pulling the trigger on a new PC. I also know that SLI and Crossfire are all the rage in the magazines. But I have some questions for those of you with these setups.

1. Do you keep any standard PCI slots after installing two cards in either configuration?

From what I can tell, at best you get to keep one remaining PCI card slot after plugging in two PCI-E cards in SLI, but I believe you can get one back with aftermarket gpu fans that are smaller than standard. I also believe Crossfire is a bit better with regard to this issue, but not sure at all. The magazines never mention anything about this stuff of course.

2. Is it worth it?

From what I can gather, all the testing is done in these magazines at 1600*1200 with all the eye candy turned on. Even at these levels, the "inferior" ( such as the X1800 or 7800GT) cards are putting out some impressive numbers. Can I really see a difference beyond, say, 30 frames per second? I think not, but not sure here.

So what about the rest of us who typically have monitors with a 1280*1040 or 1040*760 max resolution LCD monitor. I would think any modern 256mb video card can run any game quite well at these settings, but again, not sure really sure.

Myself, I'm I would eventually like to install a PCI based broadband antenna, sound card and one of the new PhysX processors which are quite interesting and seem to be able to add play/visual value to a game beyond just higher framerates that I probably can't see anyway with a second vid card.

But, if I can have my cake and eat it too, why not? In this case it means a motherboard that would allow me to use a dual video card setup is desired and let me keep all the other PCI goodies I'm thinking about.

Is this possible?

Tom