The Red Vine Window Box, left, is on sale for $71 and looks pretty traditional. The Modular Window Box, right, is $79 and definitely more contemporary. We see it hanging out a window of a modern, minimalist building.
Both of these would hold individual pots rather than loose dirt, but there are other options for those of you who want to plant one big trough. Some get a little pricey, but if you're looking to invest, at least they're on sale.
Check out other styles at Smith & Hawken.
(Images: Smith & Hawken)