How was Voyager produced anyway? Was it done on film like TNG? I think VOY made extensive use of CGI..all of that would have to be recreated...or maybe not...I read rumors somewhere that Voyagers CGI was actually produced in a res higher than full HD...not sure what it acutally true.
Well..I would prefer DS9 first anway, because thats the series besides ENT that I havenīt seen more then 90%.
Everything from TNG season 1 until I think about season 3 of Enterprise -- well, the live action stuff, anyway -- was done on film. So all of DS9 and Voyager's live action footage is sitting in a vault in all its high resolution film glory.
The visual effects are trickier, of course. TNG's visual effects were edited and composited on video, but the original motion control model elements were all shot on film first and then transferred to video. So when they are doing the HD versions, they can actually go back to the original film elements and recomposite them in most cases. With only a handful of exceptions -- such as the soliton wave -- there was no CGI used in TNG.
But DS9 and Voyager both make extensive use of CGI. And unless they were originally rendered at HD resolution, which I doubt considering Enterprise's were only done at 720p, then those all have to be re-rendered (if the original files are still available) or re-created from scratch (if they're not). So, ironically, it may be more difficult to get DS9 and Voyager into HD, even though they're newer series.