Oh, I got lots of those.
Ours - Good band, definitely deserve more recognition. They kind of have a Muse/Radiohead sound going on. The singer Jimmy Gnecco also does some solo work, which is also good.
http://myspace.com/oursmusic
http://www.myspace.com/jimmygneccosolo
Local H - This band has a huge underground fan base and they're still putting out good music (at least I think it's good) so I'm not sure why they aren't more popular. Their myspace page isn't working for me right now (maybe it'll work for you), so I included two youtube videos.
http://myspace.com/localh
http://youtube.com/watch?v=OdCqzEdG2DQ
http://youtube.com/watch?v=3eT69nguAWk
(cover of Britney's "Toxic")
Jack Off Jill - They should of gotten more attention during their career, excellent band that was basically overlooked. Of course, there's Jessicka's new project Scarling., but Scarling. just doesn't quite compare to JOJ.
http://myspace.com/jackoffjill
http://myspace.com/scarling
Retrograde - A Canadian band that I stumbled across a few years ago, I was very impressed with what I heard. From what I understand, they're fairly popular in Canada... but have yet to break through in other Countries.
http://myspace.com/retrogradeband
Apoptygma Berzerk - One of my all time favorite bands, though I'm not crazy about their last couple albums... their earlier work is much better.
http://myspace.com/apoptygmaberzerk
Flesh Field - Excellent industrial band, not very well known though.
http://myspace.com/fleshfield
and of course... London After Midnight. I think you already know how much I love this band, Sean Brennan is really great at what he does and this band should definitely get more attention.
http://myspace.com/lam
hehe, people that read my answers on a regular basis are probably wishing that I'd shut up about these bands, but they're among my favorites and I feel the need to get their names out there. :)
Edit:
Thought of another.. Snake River Conspiracy - Awesome band, though they haven't released an album since Sonic Jihad (2000) and Tobey (the singer) is in and out of the band. I'm not sure if she's currently in or out, but she does have a solo career going on as well. With or without Tobey I hope they release something soon.
http://youtube.com/watch?v=tEYL8nUjLCs (unfortunately this is the edited version in order to avoid a violation.)
http://youtube.com/watch?v=cSJP38VBbBw (cover of "How Soon is Now?")