One of the things mentioned here (and that I've discovered) is that there are LOTS of dungeon tile sets, but very few "modern" tilesets (like office buildings, etc.). I suspect it's because modern buildings are more boring than dungeons, but whatever the case, I've been working on a set of tiles that should be good for "modern" maps (and just in the interest of full disclosure, the office set was inspired by the 3D-ish top-down look used by Matt P. in his very awesome set he posted here about too).
There are two screenshots attached - one is a set of tiles for roads, and one is a somewhat generic "office," even including ugly carpet. In any case, I'm polishing these up and hopefully I'll be able to get them into the marketplace soon. There are no gewgaws or objects (like furniture, etc) in these sets. I'm debating whether to include them, or leave that for others.
Anyway, feel free to critique, suggest things, etc.