The Categories Broken Down

Arcade Fire - Funeral
Break out the Hypercolor and headbands for the Arcade Fire category which contains music with thick textures as well as a hint of the Eighties. The tempos are more upbeat than most while not being mistaken for anything near heavy metal. Everynow and then you will be driving down the road finding yourself goobing out to one of the these tunes while yelling lyrics at the top of your lungs.
Bloc Party - Silent Alarm
Interpol - Antics; Turn on the Bright Lights
Spoon - Gimme Fiction; Girls Can Tell

The Postal Service - Give Up / Wilco - Yankee Hotel Foxtrot
The second category is somewhat of the Laptop pop category if you will. It involves more electronics as well as noises to accompany the melodies. This is currently my personal favorite.
The Flaming Lips - The Soft Bulletin, Yoshimi Battles the Pink Robots
John Vanderslice - Cellar Door
Bright Eyes - Digital Ash in a Digital Urn
Wilco - Summerteeth
Death Cab for Cutie - Transatlantacism; We Have the Facts and We’re Voting Yes; Photo Album
Gomez - In Our Gun
Morcheeba
Bright Eyes - Take it Easy (Love Nothing) EP
Radiohead - Kid A
Stars - Set Yourself on Fire

Neutral Milk Hotel - In the Aeroplane Over the Sea / Bright Eyes - Lifted or The Story is in the Soil Keep Your Ear to the Ground
The next category is what I think of when I hear the word indie. It is more emotional music with raw lyrics and voices. Particularly, Bright Eyes - Lifted has been known to bring tears to the eye. This album was put out before Conor got on a soapbox about the Iraqi war. It is phenom. Also, another point worth noting is about the singer of Neutral Milk Hotel. Jeff Mangum basically freaked out and disappeared from the US. I believe he is currently in Bulgaria making music.
Pavement - Crooked Rain, Crooked Rain: LA’s Desert Origins; Brighten the Corners
The Decemberists - Picaresque; Her Majesty The Decemberists
John Vanderslice - Cellar Door
Spoon - Gimme Fiction, Girls Can Tell
Wilco - Being There
Bright Eyes - I’m Wide Awake Its Morning
Bright Eyes - Lua EP
The Shins - Chutes Too Narrow; Oh Inverted World
Death Cab For Cutie - Transatlantacism

Son Volt - Trace
This category is basically the alt-country category pioneered by Uncle Tupelo who later split into Wilco and Son Volt. Before Ryan Adams turned into a wuss, he made beautiful music with a band called Whiskeytown. Check it out.
Drive-By Truckers - Dirty South; Decoration Day
Cleotis - Cleotis
Damien Jurado - On My Way to Absence
Richard Buckner - Since; Devotion and Doubt; The Hill
Ryan Adams and The Cardinals - Cold Roses
Whiskeytown - Stranger’s Almanac
Uncle Tupelo - Every Album
Wilco - A.M.
Kings of Leon - Youth and Young Manhood; Aha Shake Heartbreak
My Morning Jacket - Tennessee Fire
Sun Kil Moon - Ghosts of the Great Highway
Bright Eyes - I’m Wide Awake Its Morning

My Morning Jacket - It Still Moves
This category is hard to label. It is somewhat of a southern rock feel with a classic rock background. The lead singer of "the jacket" Jim James is a right good looking chap with hair down to the middle of his back. Oh wait a minute, he chopped it all off and now looks like a young prince. He rocked harder on stage with long hair, no doubt.
My Morning Jacket - At Dawn; Acoustic Citsuoca EP
Kings of Leon - Aha Shake Heartbreak; Youth and Young Manhood
Drive-By Truckers - Dirty South; Decoration Day
Spoon - Gimme Fiction, Girls Can Tell
Gomez - Bring It On.
The Strokes - Room On Fire

Belle & Sebastian - The Boy with the Arab Strap; Tigermilk; If You’re Felling Sinister
This category is more of a laid back category with tunes to ensure you that you are comfortable with your sexuality. Although at times you will feel as if a male should not listen to this, it is sinless guilty pleasure. Each of these albums provide more of a relaxing atmosphere.
Andrew Bird - The Mysterious Production of Eggs
Stars - Set Yourself on Fire
Iron & Wine - Woman King EP; The Creek Drank the Cradle; Our Endless Number of Days
Bonnie Prince Billy - I See a Darkness
Bonnie Prince Billy & Matt Sweeney - Superwolf
Damien Jurado - On My Way to Absence
M. Ward - Transfiguration of Vincent
Yo La Tengo - Summer Sun
Wilco - A Ghost Is Born
My Morning Jacket - Acoustic Citsuoca EP
Death Cab For Cutie - Forbidden Love EP

Modest Mouse - Good News for People Who Love Bad News; Moon & Antarctica
On the other side, this category is borderline hard rock. These bands are not afraid to sing and play with their guts. You will find yourself "meating out" on some of these tunes. Disclaimer: Modest Mouse's Lonesome Crowded West I must warn you that someone has actually received whiplash from Doin the Cockroach which is Track 6 on the album.
Pavement - Slanted and Enchanted: Luxe and Redux
Swell - Too Many Days Without Thinking
Modest Mouse - The Lonesome Crowded West
Spoon - Gimme Fiction; Girls Can Tell

The Go! Team - Thunder, Lightning, Strike
This category contains the instrumental music. Although I must admit none of the following are as amazing as The Go! Team, the following albums are still ear friendly. Many of the following albums come highly recommended when looking to score.
Air - Talkie Walkie; Moon Safari
Mogwai - Happy Songs For Happy People
Thievery Corporation - The Cosmic Game, The Richest Man in Babylon
Bela Fleck & the Flecktones - Live Art
Leo Kottke - Anthology
LCD Soundsystem - LCD Soundsystem
Broken Social Scene - You Forget It in People
M83 - Before the Dawn Heals Us
Sigur Ros’ - ( ); Agaetis Byrjun