|I'm partial to Heavy Metal/Rock while programming to keep the energy up.|
In that case, you might enjoy power metal. It's like regular metal at twice the speed.
Rhapsody (of Fire): Everything until 2001 is great. From 2002 on, it's more symphonic than power. They still have some great songs, but in a much lower proportion than their earlier albums. I think it's worth noting that I listened almost exclusively to their songs for over a year without getting bored.
Lyrics: The first five albums make the Emerald Sword Saga, a typical high fantastic tale. The other two follow a similar formula.
Favorite songs: Eternal Glory (properly listened to immediate after Heroes Of The Lost Valley), Land of Immortals (again, properly listened to after Virgin Skies), Rage of the Winter, Holy Thunderforce, Where Dragons Fly, The Wizard's Last Rhymes.
Sonata Arctica: To be honest, they only have a couple songs worth listening to. The rest is just too gay. Even for power metal standards.
Favorite songs: Unopened, San Sebastian, The Cage.
Sabaton: More heavy than Rhapsody, it's a relatively young band (they began around 2002-2005. Rhapsody began in 1995 and others like Manowar are even older) but really good. All of their albums are worth listening to.
Lyrics: An unusual theme, they sing about historical battles, usually from WWII.
Favorite songs: Into the Fire (Vietnam), Attero Dominatus (battle of Berlin), Back in Control (Falklands), 40:1 (battle of Wizna), Firestorm, Hellrider.
HammerFall: I found this one recently. I like them better than Sonata Arctica, but less than Sabaton.
Favorite songs: Templars of Steel, Renegade, On the Edge of Honour, Heeding the Call, HEarts on Fire.