Do you have a particular usage scenario in mind for the dual monitors?
Typically I'd have a primary and a secondary, so the secondary would be fine with VGA, but it depends on what you plan on doing.
Also try the digital on the TV and see how nicely it plays (i.e. is it easy to get it working at a proper resolution that fills the screen) and test it vs using the VGA. If one plays nicer than the other, that kind of makes the decision for you (unless you are doing heavy text work on both monitors and want DVI to make sure they are both sharp)