gastrof, I am so sorry you lost so much. I'm glad you are personally okay.
Choice 3: TOS DVD -- Some purists may point out something to do with the sound mix here, but I consider any such differences so minor and trivial compared to the other improvements offered by the remastering that I find nothing compelling about this set to recommend it (unless you wish the original VFX but cannot afford the blu ray)
As probably the one "purist" who has made the most noise about the sound mix, I'll chalk up the "trivial" aspect to personal preference. I do admit, I'm probably in the minority. That being said, the DVDs don't contain the original sound mix, so that's not an advantage to buying the set. The original sound mix is only available on the old VHS and Laserdisc editions (and the season one BDs), so that's not an option.
There ARE reasons, however, to get the standard DVD versions that don't include the sound.
1. If he didn't replace his HD TV there's NO point in buying a Blu-Ray player. The screen ratio is adjusted so 4:3 presentations, like Star Trek, will be made even smaller thanks to forced letterboxing. So it just comes down to a choice of which set to buy, which was his original question.
2. Even with an HD set, the original effects look better in standard def. Mike Okuda is right, the old effects don't hold up at all under the harsh light of HD and when they remastered them from the materials at hand, they wound up looking worse than before. Compare the opening shot of "Let That Be Your Last Battlefield" and see how incredibly grainy the original footage is on BD, but is a lot smoother on DVD. On a standard def TV, the DVDs look incredible. On an HD set, the standard DVDs still look great and the colors are not nearly as garish as the BD. I watched some episodes off the season 2 DVD set last night and enjoyed the original effects more on DVD than I do on BD.
There's not much else, really. I am of the mind that HD reveals too many faults and pulls the curtain back too far on old TV shows and movies. I was fine not seeing Shatner's toupee line, or his lace up boots in Arena, or the makeup seams on Spock's ears. The producers and staff used the lesser resolution to hide things. They're revealed now, which ruins the illusion. When you see a magician do a trick, you WANT to be fooled. You don't want to see or hear the forklift levitating the assistant. Also, the colors seem too bright and the rest of the image too dark in comparison to previous versions. I felt the DVDs got the picture just right and that BD was overkill. But, as with the sound mix, I'm sure I'm a party of one. Doesn't much matter, I have every version on video to watch according to my mood. Paramount got my money doeznes of times over for these episodes.
So, my recommendation, gastrof: if you didn't get an HDTV, I'd go with the original versions on DVD, because as much as I enjoy many of the CGI effects, I'll always want to watch the originals. If you have an HDTV and can get / or have a blu-ray player, see if you can get the sets. But the DVDs look fine in any event and do the original effects more justice.