Here is my opinion too, although the other guys pretty much covered the stuff
Summoning
Atmospheric black metal, synth-based, with programmed drums (which is not a bad thing). The only problem is that they are a bit repetitive in their style between albums.
Recommendations: Dol Guldur, Minas Morgul
In The Woods
They've started as melodic, pagan black metal band to evolve into one of the best progressive atmospheric bands ever. Every album is unique and every one is a masterpiece
Recommendations: discography, but get first Omnio, then HEart Of The Ages, 3 Times 7 In A Pilgrimage, Strange In Stereo and if you want A Return To The Isle Of Men (demo)
Ulver
What can I say about them? My all-time favorite band, in my opinion the definition of progress in music. Every album is totally different than the rest.
Recommendations: once again discography. Here's a brief description of every album
Bergtatt - melodic folk black metal
Kveldssanger - folk (totally acoustic)
Nattens Madrigal - old-school black metal (like Darkthrone)
Themes - rock, pop, metal, trip hop, electronica, etc (if anyone can clearly describe this amazing album, I'd like to know)
Metamorphosis - electronica (from dance to more atmosperic approach)
Perdition City - lounge, chill out, trip hop, jazz etc.
Silence Teaches You How To Sing - a more relaxed approach to the style of PC, with some noise touches
Silencing The Singing - same as the previous
Lyckanthropen Themes - a soundtrack similar to the last two eps, very good
Pain Of Salvation
One of the best new progressive metal bands, with influences from Dream Theater, Tool etc. Technical but not too technical
Recommendations: The Perfect Element Pt. 1
Maudlin of the well
The best progressive death band right now (I'm not trying to be offensive but these guys are much better than Opeth in my opinion).
Recommendations: Bath, Leaving Your Body Map
At the gates
Melodic swedish death metal band. One of the creators of what was named afterwards N.W.O.S.D.M, they manage to be melodic and technical whithout losing their aggression.
Recommendations: Slaughter Of The Soul, Terminal Spirit Disease
Dream Theatre (which albums should i get first,or should i get?)
While many people here find them boring and unemotional, I think they're neither. I love them and believe that their music is emotional if you take the time to listen to them carefully.
Recommendations: Images And Words, A Change Of Seasons, Scenes from A Memory