I predict that within the next 2 years, open hardware designs really start giving semi-commodity hardware a run for its money.
Things like wifi routers, Ethernet switches, add-in cards, and input devices. The time of the somewhat specialty non-open hardware design is coming to an end.
Given the capabilities of the BeagleBoards and the neTV, Shapeways, lower cost FPGAs, open source micro controller development environments, and lower cost hardware design tools: there's going to be a really fun shake up the hardware landscape. Combine this low cost (to develop) tech with KickStarter type funding and I expect a large number of open hardware companies will emerge in the next few years.
The early adopters will be power users who don't mind a few inconveniences at first in order to support awesome products (just like on the web or with software). After about a year of an open hardware product being out, it'll start leaking into the masses. Then it will all be over. There will be a commoditization of hardware in the same way open / free software has commoditized a huge swath of the software landscape (open / free web servers run a HUGE portion of the web). Traditional vendors of hardware will start using the open / free hardware as a basis for their designs because it will be cost prohibitive to do otherwise.
We've seen this before with software. It's to the point now where if you're building a product with an embedded computer in it, you pick GNU/Linux (or Android which uses Linux, the kernel at least). It's too expensive to do otherwise, there's just such an awesome set of base open / free software available.
I'd love to be on the forefront of the open hardware wave. I'm not, yet. It's just starting now. I better get crackin'...