Well, I'd buy Voyager, too ... but yeah, DS9 comes first on my wishlist.
Yeah, I don't think I could even say this. I'd watch it. Maybe rent it. Maybe buy some of the latter seasons but Voyager is just a show I watch when its on. And even then Im more likely to change the channel than watch it all.
DS9 on the other hand, I go back and rewatch that all the time, just like TNG.
I'd rather they release Ent. I'd love to watch Season 4 in Hi-Def, especially if they give it a generous special feature treatment (which considering its HD already, is really all they need to do).
ENT would be very easy to release on Blu-Ray since it was already filmed with HD cameras.
I can see CBS releasing ENT after TNG and seeing how well it sells before moving on to DS9 if they decide to do that.
In they end, they probably already have a very good idea how popular each show is since they know how well each show sold on DVD.