well, if you've got 2xdvi, then you can run 2 dvi monitors.
my 9700pro has 1 of each, but it came with an adapter to turn the dvi into a vga.
if you are interested in running 2 dvi monitors in the future, for sure go 2xDVI, and if you need, use an adapter for now to vga.
there is no adapter to go from vga to dvi AFAIK.