Windsor West, easily. Kingsway is a pretty reliable NDP seat now. Windsor, however loves its long-time incumbents, so when Masse retires, it could be a toss-up. Not too long ago it was a reliable OLP seat when it was held by Pupatello.
And of course, before Masse federally was...Herb Gray.
Also, for all the talk about SW Ontario trending away from the Libs, let's not forget that Windsor West is an urban riding, the most "central" of the Windsor ridings, with less of a blue-collar and more of a professional-class element than Windsor-Tecumseh (and U of Windsor as well). So it'd be *very* Lib-amenable (and not especially CPC-amenable) in the event that the NDP tanks...