Straw is good, IMO. If you put it on real thickly and have a vole problem you will have a bigger vole problem, but that is true to some degree of any organic mulch.
Tip: OaklandCityFarmer is right, straw often (depending on the type of straw) can be somewhat reluctant to break down and thus difficult to till in come Autumn. One thing I've had really good luck with is to dump a layer of manure, it can be fresh if need be, atop the straw in the Fall and just leave it there (don't till). Then in spring when the soil becomes workable, dig or till it all in, it'll be easy. You do lose some of the nitrogen value of the manure this way unless you mulch on top of *that* with dried leaves or dried-out not-gone-to-seed weeds, but oh well.
Pat