If the wall tile butts into the floor tile, then I'll color-match the wall grout. If the floor tile butts into the wall tile...well, I can't recall ever doing that. I always tile the floor before setting the bottom course of wall tile. Mongo

In all due fairness, I wanted to provide a follow-up on the situation with the threshold issues we had after Lowe's installed new hardwood flooring for us back in October. It took some time, but by Christmas Lowe's fixed the problem. We promptly sent a certified letter to the store, copying all the appropriate parties, and outlined the issues with a highlighted attachment of the Bruce installation specs. In deference to our concerns, a different flooring subcontractor was brought in to fix the floor. Rather than ripping up the newly installed family room floor, it was treated like another layer of plywood subfloor, then leveling compound was used to address the dip in the floor and a second layer of flooring was run over that. From there, standard thresholds were used. We would not have had the necessary leverage without the benefit of this forum. Thanks Jerry T!

Ignore the paint swatches, but here's a decent shot of how our tile and wood flooring meets. It's in the middle of an open area (between dining and kitchen), so there is no "threshold" per se, instead, both sides butt up to a metal strip that is flush to both the wood and tile. You can see the metal a little better in this shot (and dust on the dark hardwoods - oops!)

There's only one right answer: silicone at the intersection of two planes. And if your tile guy doesn't know this, he's incompetent.