It's reasonable to think that the events of First Contact created an alternate timeline that Enterprise and Star Trek 2009 take place in. Interference from the future could explain the more advanced looking technology in the series and the movies. I also refuse to believe the events of the episode "Regeneration" took place in the same timeline as later events in TNG.
IMO the way the technology or sets looks means no more than the way the actors look. If a character can be recast, than the sets and props can, too and be no more different than Saavik was in STIII.
I also don't hold any episode or movie as absolute "fact" - Trek holds together in broad strokes
only. Take a look at the YouTube videos in my sig to see just how broken the continuity is when you take everything literally. At the very start of the novelization of Star Trek: The Motion Picture, Gene Roddenberry has Kirk dismiss The Original Series as an inacurrate dramatization of Kirk's five-year mission. Kirk flat out calls it "foolish heroics" and "exaggeration" and says he'll not allow such in the future. I bet GR would love the new movies
I hear the First Contact AU excuse a lot, but it doesn't hold up under scrutiny - FC is referenced several times in Voyager (and in fact, "Regeneration" neatly explains how Seven knew of the past events of FC!), which launches from Deep Space Nine and crosses over with TNG and STVI and mentions FC. DS9 crosses over with TNG and TOS, TOS crosses over with TNG and nuTrek, etc etc. - it's a big tangled web, you cut one or two bits off and it just makes more of a mess because the bits that used to add up, don't anymore.