Start with Killers, Piece Of Mind, Powerslave, Somwhere In Time in that order.

These are Maiden's 4 best IMO.

Number of the Beast has some of their most popular stuff but quality wise it isn't in their top 5.

Ive mentioned this song before..and I like it so well I just have to post the link, I do know that it was on a soundtrack off one of the movie sequels 'The Crow'.
YouTube - Hurt - Rapture

I'd like to recommend a band called ZeroZonic.

They play music similar to Pantera and Chimaira, a fine mix between groove metal and thrash metal. Seen them live, and a great band with lots of energy.

Check them out!

ZEROZONIC on MySpace Music - Free Streaming MP3s, Pictures & Music Downloads

I'm looking for ambient/trance psychedelic music. I've already listened to Shpongle quiet a bit and am wondering if there are any other psybient groups out there that are worth listening to.

Now I am completelly fascinated by band Agalloch :)

They are not easy to describe... Mixture of dark metal, neo-folk, post-rock and progressive. Electric and acoustic guitars, sometimes piano.
If you like Opeth, you will probably like this band too.

Somewhere In Time is by far Maiden's best album. Number of the Beast sounded good in it's day, but hasn't stood the test of time.

Petula, I like the somber feeling of both songs. You describe them well.

I especially like the instumentals and the times when the singers *aren't* growling. The growling in songs just feels so impersonal to me, and it makes me stop and think, "Oh yes, the person is growling to show he/she can growl," which distracts me from the emotion behind what is being growled.

Since often the growling makes hearing the words difficult, I also feel some animosity toward growling, because I think it makes understanding the music more difficult.

I guess I really just prefer people's talking/singing voices...they feel more individual and unique than growling long passages. I agree, though, that what I admire about these two songs by Agalloch is very similar to what I admire about Opeth...the cleanless of the drums, the energy, the changing beat patterns, and the feeling of foreboding and all is not well.

As I lay dying

or opeth.........lol

anyone know of any space rock bands, similar in sound to the clean-vocal breaks Between The Buried And Me often incorporates in the middle of some of thier songs?

Hibria- pretty sweet power metal group