HD4850 crossfire dual x8 versus x16

i've seen so many benchmarks etc. about dual x8 vs dual x16 and i've gotten so many different results.

i recently bought a 4850 and i'm using it on my pci-e 1.0 motherboard at the moment. (which is performing amazingly well. runs crysis very high and is totally playable.) gpu-z says i'm getting 67.2 GB/sec bandwidth. i don't have anything to compare that to though, is that good/bad?

i'm looking to get a 4850 crossfire setup and was looking at this board
http://www.newegg.com/Product/Prod [...] 6813130172
which runs x8/x8. it's really cheap for a pci-e 2.0 board, but would it be worth it to get a board that runs x16/x16?
the x16/x16 ones i've seen are basically twice as much. is it worth it?

OR

if i don't go the crossfire route would it even be worth it to buy a new motherboard to upgrade to pci-e 2.0?


thanks


p.s. i did also post this in the graphics cards forum; multiple opinions are always nice.