Well, I for one would definitely prefer 1". I don't think I'm in the minority, as the recent hubbub about CWU should attest.
I think the best thing, really, would be to make it in both 1.5 and 1. I know that is more work, but by having a broader appeal, you're keeping your sales more open. While a lot of people will want Spaceworks for Heroclix or the new Star Wars Miniatures (not even sure if that's 1.5" or 1"), there will be many (like myself) that would want it for non-clicky games like RPGs and wargames (I think Spaceworks may have some appeal to Warhammer 40k players).
Of course, the absolute best would be to have it like the Maiden, with 1", 1.5" and no-grid options. That is the most work, too, though.
