Just getting this out there. A lot of people know how there's options in windows to allow windows to "snap" together if they're within 5 pixels. Why not the same for Prims within Second Life. I know it wouldn't be that hard to impliment. Just a small extra script to shift it if the two prims are within a a certain distance. This would make it a lot easier when building things like houses and rooms. Walls would snap together and there would be no gap. Same thing with floors. Textures would be a lot easier to line up than having to zoom in with the camera and tweak it oooooo so slightly.
Of course you'd also want the option to turn that off for some work. Of course, this will probably get ignored.