They are really spot on!!! i cant modify it oned bit except maybe Charlie having a hobbit drinking song
:D

They don't need theme songs! Michael Giacchino's an absolute genius, his soundtrack cannot be beaten by anything available in popular music. No matter what songs we pick, they will be much, much worse than the official soundtrack.

here's an idea:
sawyer-chasing girls by rodney atkins

Jack the drugs dont work by the verve or yesterday
by the beatles
rose and bernard stand by me
Sawyer behind blue eyes
kate nobodys home by avril lavinge
christian shepard rose by the feeling
skate cry me a river
all cast all fall down by one republic
ben and juliet i dont love you by my chemical romance
Shannon my skin Natalie Merchant
Charlie and Claire make you feel my love by Adele
Jin and sun like the sun by ryandan
Charlie the fear by lily allen or wonderwall or wave goodbye by steadman
Shannon and boone foundations by kate nash
claire suddenly i see by kt tunstall
all cast its not over yet by the klaxtons
Eko hallelujah
James and juliet im yours by jason mraz
Kate and aaron in my arms by plumb
jack and kate we belong together by gavin degraw or dancing by elisa
locke gravity by embrce or a change gonna come or dead and gone by ti and justin timberlake
charlotte and dan the blowers daughter by damien rice
micheal tourniquet
penny and desmond the reason
all cast run by snow patrol
sayid leave out all the rest by linkin park
daniel geek in the pink by jason mraz
all cast street lights by kanye west
ben help by the beatles
kate and juliet jolene
all cast hometown glory by adele
ana lucia carry you home by james blunt
hurley and libby slipped away
ben requiem for a dream
hurley buttons by sia
cast deaths why by annie lennox

Daniel Faraday - Losing My Memory: Ryan Star

Jack - "Jumper" by Third Eye Blind

jelous guy ben and juliet

Daniel - Unwell by Matchbox Twenty
Jack/Juliet - Check Yes Juliet by We the Kings
Jack - Fix You by Coldplay
Ensemble - You Found Me by The Fray
Daniel/Charlotte - Your Guardian Angel by The Red Jumpsuit Apparatus

These songs could work with either Jack and Kate or Charlie and Claire:

"Hero Heroine" - Boys Like Girls
"Your Guardian Angel" - Red Jumpsuit Apparatus

Jack/Kate:

"Halo" by Beyonce.

Ensemble - "We Are Broken" by Paramore

Eclipse64 i think Daniels theme song is really awesome1

For Kate I found Misguided Ghosts-Paramore and I picked Done all Wrong-Black Rebel Motorcycle Club For Sawyer

Jack and Kate What's Left of Me by Nick Lachey. Still trying to make a video with it. But it's hard. And also thinking abou Jack and Kate when i listen As Long As You Love Me by Backstreet Boys.

Michael Giacchino: The Lost OST

seems to work for most characters.