Gamasutra has just published an excellent feature article on the history of the GCE Vectrex console, by Bill Loguidice and Matt Barton of Armchair Arcade (Matt is also a contributor to Gameology). Their article covers the history and hardware of this odd and wonderful system, which I'm quite fond of. As anyone who has recently visited my apartment knows, I acquired a Vectrex a few months ago and am eager to encourage guests to try it out. So far, I only have Berzerk and the built in Mine Storm, but those are plenty fun.
One thing that continues to interest people about the Vectrex is its relative accessibility for homebrew programming. That is, compared to the Atari VCS (which lacks a screen buffer), Vectrex features a well-documented BIOS and readily available compilers on the web, if I'm recalling correctly from poking around a while back. That, plus the fact that the owner of its copyrights have graciously opened up the entire catalog to public domain make it a great homebrew platform.
Its quirks are fun, too, like the characteristic hum (due to poor shielding) and the way the music always sounds slightly out of phase (to me, anyway). I don't have much to add that Bill and Matt haven't covered in depth, so go read their article.