You are missing out!!
Here is a listing of some music (songs, artists, styles, albums, bands) that I feel are overlooked and are fantastic.  When I ran across each, I was blown away and wondered, "DAMN, how could I be missing out on this."  Read this page and you'll miss out on that much less great music!
Soft Jazz
Yeah, it's sissy or "old people" or "department store".  But when you want to relax though, it cannot be beat... you just have to pick the right stuff.  Currently, I'm stuck on listening to Diana Krall.  She does a version of Joni Mitchell's "A Case of You" that I can listen to a million times.  I drove someone's car who had her "The Look Of Love" CD in it and instead of parking it quickly, I drove it around the block FOUR TIMES listening to the tunes!  Truly an intoxicating voice.  Ella Fiztgerald, Dusty Springfield are some others that I find similarly appealing.

George Benson is another current favorite for more instrumental stuff.  His guitar technique is so fluid you'd think it was some other instrument and the guy can sing too (I had no idea).

Rock N Roll
If you've ever known me more than an hour, you'll know much of my passion lies in good rock music.  There are a ton of great mainstream bands, but here I'll try to point out some that are missed or just older good bands and albums that have fallen away but are still valid.

Failure is a band that cannot be missed.  The melodies are so unconventional and the tones so divergent from mainstream... yet... you can listen to it easily.  Great stuff.  At first it may be a bit akward, but give it just a bit of time... and the lyrics DO make sense.  This is genius at it's best.  Some high points are "Empty Friend", "The Nurse Who Loved Me", "Smoking Umbrellas", "Moth", "Pillowhead", "Blank". 

They've got two albums worth buying right now...
Magnified and Fantastic PlanetMagnified is a great collection of songs, whereas Fantastic Planet has an actual flow from song to song... and back again (listen to the ending and then the beginning... how cool is that?!?!)

Unfortunately, there is no more Failure... the band broke up, but check out the WWW and you'll find newer projects by Ken Andrews and Greg Edwards that are worth a listen.

Big Wreck is my favorite band.  That's it... my favorite.  I don't dish this praise out easily either.  The music is huge in every way.  The singer/songwriter just pours out emotion in the songs.  Creative lyrics have me coming back again and again, seeing it a different way or relating to it in a new way.  The tones are second to none... intoxicating rock at it's best.  I can listen to either of their albums over and over and over and not get sick of it.  Everyone I turn on to this band thinks they're great too.  It is an unfortunate state in the music industry when MTV pedals schlock as "great and new" and bands like Big Wreck fall by the wayside.  This band is NOT to be missed.

As a starter, I'd check out "That Song", "Ill Advice", "All By Design", "The Oaf"... ya know... just go buy both albums.  I can't say that about much but seriously... you're missing out.  Get
In Loving Memory Of... and then get The Pleasure and the Greed.  Ignore the album art  and just put it in and listen.

Ian Moore This dude defines "cool".  Ultra humble and collected... but emotional and expressive.  He's put aside his old "guitar hero" status and is now just a great rocker.  If you can possibly see him live, do it, at all costs.  This is my favorite live show to see, hands down.  Guys, girls, everyone likes his show, even if they've never heard a tune.  The music is so pure and expressive.  It's hard to describe... there are lots of blues/bluegrass influences, but it is definitely rock and roll.  Not "heavy" at all, like a lot of rock that I like... it's just good, old-fashioned rock and roll.

For albums, I absolutely love
And All The Colors and Grassroots.  I think these two are good to get you started on Ian Moore as one shows his newer, full-electric-band music style and the other has some simplier, more solo- acoustic stuff and songs that just somehow seem "close".  You'll see.

If you just want some individual songs to explore, check out "Coming Around", "Elephant Tears", and "Blue Sky".  That will give you three distinct sides of Ian Moore and hopefully turn you on to another rocker that the music biz just can't seem to handle.
I also want to just list some songs that "get into me".  These are the tunes I cannot escape and are "must haves".  Most are also "overlooked" and thus fit this page well.  This is not organized and I'll just throw up some new ones here and there.  This will be current stuff.

Tonic - Lemon Parade
Marcy Playground - Sherry Fraser
Creeper Lagoon - Keep From Moving, Wrecking Ball, Sunfair
Bob Schneider - Blue (I think this is w/ Mitch Watkins), Losing You
Ian Moore - Today, Plastic Patrick
John Mayer - St. Patrick's Day, Why Did You Mess With Forever
Diana Krall - A Case of You  (it's a Joni Mitchell cover... incredible)
Big Wreck - All By Design
Cake - Guitar, Satan Is My Motor, Italian Leather Sofa
Music is my favorite subject so this will be updated often... right now it's just a "touch" of what it will be.  Heavily under construction.