Need a graphics solution, PCI-x or PCIe

PCI video card - 9250 vs 5500

im in a little pit and cant figure out which way is the best way to get out. i have this really nice computer. dual xeon, 2gb of ram, raid 5, 200gb hdd and a freaking 7000ve. the expansion slots on the computer are ridiculous. it has 4 PCI-X, 1 PCI, 1 PCIe 8x, and 1 PCIe4x. i have no idea how im going to upgrade this. anyone have any ideas?
-its a dell poweregde 2800. the expansion slots are quick release...could i replace this for one with an AGP or PCIe 16x?
-there arent any PCIe 8x on the market rite?
-the best PCI video card would be an ATI 9250 256mb/ GeForce FX 5500 256mb? what about the Quadro 4 400NVS?
-any ideas/hope on making those cards any faster than a 9600?

400NVS is a great card if you like multi screens! I once had 2 of those in a computer running together with a NVS280 10 screens simul...fun fun fun - but for gaming it's too slow...

thats sweet mikeguava, running 10 monitors. unfortunately ill prolly only get to dual monitors if im lucky.

turns out that 400nvs is pricy. saw it at compusa for 500ish. why is that thing so expensive?! can it do 3d rendering for 3d moldeling software or something?

but it looks like im stuck with either a 5500 or a 9250. im liking the 5500 b/c of the dx9 support. how is its oc potential?