Since you don't seem to be overclocking, the decision is pretty easy. Just get a board that will support your CPU and has two PCI slots and one PCIe x16 slot that supports your CPU.
You may also want dual-channel RAM support (rules out NVIDIA 7000 series chipsets) and a more recent chipset (rules out G31 chipset). Also, having 4 memory slots would probably be nice, right?
This leaves NVIDIA 9300/9400 chipset and Intel G41/43/45 chipsets.
Just do a
power search on Newegg with these items checked:
Product Type: Retail
CPU Socket Type: LGA 775
FSB: 1333/1066, 1600/1333
North Bridge: NVIDIA GeForce 9300, NVIDIA GeForce 9400, Intel G41, Intel G43, Intel G45
Number of Memory Slots: 4x240pin
PCI Slots: 2
Form Factor: Micro ATX
Leave everything else checked to the default of "Any" and click on Search.
I see 9 results, so that certainly narrowed down the field. If you want the newer PCI Express 2.0 x16 slots for the motherboard then you can leave the NVIDIA chipsets unchecked. This will result in a total of FOUR results.
Your video card is a VisionTek 4850. The only one I see on Newegg is a dual slot card, so you have to be able to accomodate that while not blocking the PCI slots. This leaves a total of TWO motherboards:
MSI G45M-FD
Foxconn G45M-S
Those use the same chipset. Their display outputs are vastly different though, with the MSI offering DVI and VGA while the Foxconn offering everything EXCEPT DVI (HDMI, VGA, Display Port). You're not using onboard video though, so let's look elsewhere. Pretty much same Realtek gigabit ethernet and audio chipsets. Oh, the Foxconn board uses the more expensive ICH10R Southbridge which supports RAID. The MSI has a printer port and IDE port for legacy devices. Foxconn officially-unofficially supports overclocking. Foxconn has Firewire. MSI has better coolers on the chipset. Oohh, MSI uses solid caps on just the CPU while Foxconn uses solid caps everywhere. MSI uses a 4-pin CPU power plug while Foxconn uses 8 pin. The MSI power plug is towards the middle of the motherboard while Foxconn is on the edge which is better. The Foxconn board will potentially lose fewer SATA ports due to huge dual slot graphics cards (GTX 295?) than the MSI due to being blocked. Foxconn overall has better Newegg reviews (taken with grain of salt).
I personally have my eye on the Foxconn G45M-S for my LAN gaming rig (hmmm, might order it this weekend). I'd say it is a win for Foxconn as long as you don't need the printer/IDE ports. What the Foxconn has over the MSI are better overal capacitors, slightly better layout, overclocking
See, wasn't it easy to choose a motherboard?

Just look for one that has the features you need along with some logic and it pretty much chooses itself!