KVM / DVI / VGA

Need advice on DVI/VGA vs KVM switches.
I have been looking at a IOGEAR GCS932U 2 Port DVI-D KVM with Audio

http://www.iogear.com/product/GCS932U/

This seems to be a nicely sized multifunction kvm, (don't really want a clunky box type).

Problem is, I want to tie the main pc monitor into the kvm switch using a dvi display connection, but at times need to connect older pc's (second pc on kvm) with a dvr display connection, as some older pc's do not have dvi capabilities what's my best option here?

Thanks
N2