Shouldn't everyone first mention what they LIKE, before they try to tell other people what to listen to? So you listen to stoner death metal?
You listen to hippy, neoclassic progressive nu-metal? Great. But that's not what I'm interested in.
So here's the idea: I like stuff with good melodies. I mean, it's gotta be catchy. Whether it's happy or subdued is irrelevant: It simply needs to be melodic. (Think, Stratovarius, Rhapsody of Fire, Blind Guardian, Freedom Call, and Dragonforce)
So here are my recommendations if you want stuff with good melodies (and most of this is fairly technical; I don't subscribe to the Axel Rudi Pell school of repetitive thinking/playing )
Freedom Call
Dragonforce
Stratovarius
Rhapsody of Fire
Blind Guardian
Twilightning (First two albums; trust me, the last album before they broke up is HORRIFIC)
Galneryus
Dreamtale
Airborn
Sabaton
Agonizer (Blew me away the first time I listened. With a name like "agonizer," I wasn't expecting much)
Timeless Miracle
Falconer
Astral Doors
Wuthering Heights (Agggh, how can a band be this awesome?)
Angra
Aquaria (Some of the best stuff every made. I can listen to it over and over. Start with "And Let the Show Begin" )
Nocturnal Rites (I actually prefer the old stuff, but still like the newer stuff)
Edguy
Avantasia
Gamma Ray
Cellador
Dream Evil
Primal Fear
Axenstar (One of the less impressive ones, but some people love their slightly surreal atmosphere)
White Skull
Power Quest
Bloodbound
Axxis (Their newer albums are more "power metal" than their older, hard rock stuff, but it's all good)
Derdian (All albums have good songs, but their newest album has the best production quality, and some of the best, most musically impressive songs)
Celesty (Really only necessary to check out their latest album, Vendetta; a masterpiece)
Excalion (More straightforward, without much in the way of keys, but the singing and melodies are awesome)
Northern Kings (A cover band, but MAN are they talented)
Machinae Supremacy
Adiastasia (If you can tolerate less-than-great production quality, this band has a lot to offer by way of melodies and instrument sections)
Kamelot
Heavenly
Dark Moor (You might want to start with Gates of Oblivion)
Solar Fragment (Unique-sounding, with some incredibly powerful vocals and dynamic but engaging melodies)
Kiuas (And I thank this band for keeping the melodies and not succumbing to boring, repetitive riffage or stale melodies, like Alestorm tends to do)
Edguy
Keldian (One of the most consistently excellent bands out there, with some wonderful violins and always with melodic choruses)
Azrael (And I'm talking about the Japanese Azrael, not the-- other one. Particularly the album Sunrise in Dreamland. Start with the song of the same name. Bloody excellent in the melody department. Warning: Super high vocals)
Ride the Sky (Only one album before the band broke up; excellent)
Silent Force
Well, that's my contribution. I know some of this stuff is well-known, but some of it is less spoken-of (such as the excellent Airborn) so take a gander if you want great melodies.