Definitely not CBS. It would not live past one season, two at the most. It's interesting to note that the new V has been renewed, but I don't overly anticipate it surviving into year three. Plus, a new Star Trek would probably cost more, because... yeah. No, it certainly would.
Possibly the CW. That network has Supernatural, which can actually be decent sometimes when it isn't making sure to shove breasts at the younger demographic. That would still be a big concern of mine. We saw how much T'Pol-flashing went on with Enterprise. The same thing would most assuredly happen again, and it could be very distracting.
Spike would be a horrible, horrifying choice. Seven of Nine and T'Pol won't have had anything
on the outfits that network would force.
SyFy is probably the best choice overall, and then its survival would definitely depend upon critical reception. It would get four or five years if it gets half the positive buzz BSG got. The problem here is that I don't think CBS would let this happen. They'd say SyFy can't provide the money for it, and they'd probably be right. I read in the past that there was a brief flirtation with the idea that SyFy (Sci-Fi) then would take Enterprise for a fifth season, akin to its investments in Andromeda and Sliders in the past. The big idea was that the network just couldn't afford it, or so I hear.
Showtime wouldn't be able to guarantee the numbers CBS would want. Stargate SG-1 was considered reasonably profitable on that network for the five initial years it was with them, and I think it pulled like 400k-600k viewers or so per week. Suffice it to say, that's not the kind of numbers CBS would want. Enterprise was shot dead after four seasons because it was only pulling like 1.6 million viewers. I mean, yes, it's a different environment. But I don't know that the production values and all that would mesh with that sort of thing. I will easily confess I don't understand much at all about how premium cable networks operate, though. HBO gets all these high-end dramas but never rakes in the digits that even regular cable networks aim for. How they get away with it I don't understand.