I can't really pinpoint what my one, true favorite band right now, so I will have to name a few.
Kalmah - Excellent melody, guitar, and drum work. I'm looking out for more from them. Check Mindrust and Hollowheart if you want examples of them.
In Flames - Old or new, I like them a lot all the same. It's true I like their older stuff better, I won't deny that. I will have to point out Man Made God, Embody The Invisible, and pretty much anything older than the Colony album.
Iron Maiden - Their stuff is AMAZING. Run To The Hills, Number Of The Beast, The Trooper, The Nomad, The Pilgrim, Wasted Years, Dance of Death, Flight of Icarus, Powerslave, Aces High, No More Lies. Those songs are all epic in their own way.
Megadeth - Peace Sells, Cryptic Writings, Countdown To Extinction. I love their lyrics as much as I do their drum and guitar work. The songs, Peace Sells, Hangar 18, and Prince of Darkness need to be checked out.
Sonata Arctica - This does not need any further explanation.