Nice topic. It allows you to think for once... A lot of albums and songs have had this effect on me, but I'll list a few albums.
"Cruel Town" by swedish alternative pop/rock-band Broder Daniel. They have released several albums before that are better than this one, but this hit me in a critical stage of my life. It's about how society gives nothing for people who don't bring anything into the "system". The songs were written by the singer while he was fighting his way out of depression, something he seems to have done his whole life. Touching, to say the least.
"Nia" by Blackalicious. This album hit me like a fist to the face just as I was about to lose faith in modern hip-hop music. Innovative and exciting. If it wasn't for this album, I would never have been a descent writer of rap-lyrics (which I'm not anymore, since I quit cold turkey and havn't tried for about two years).
"Missundaztood" by Pink. Yes, I am a guy.

Heh, this may come surprising, but I'm including this here because it reminds me of the greatest summer of my life (so far). My girlfriend got the album and played it constantly for two months. I never listen to it, but when I hear songs from it playing, I get nostalgic and a bit sad over lost times. I do stand by my word that some songs on this album are actually pretty good, but since some songs are embarassing crap too, I wouldn't buy this album unless I had a boatload of money on my hands. This album also reminds me of countless hours of producing an acapella cover of the song "18 Wheeler" with my girlfriend on vocals. I had just bought her a complete basic studio equipment with a good microphone, a preamp, a mixer, etc. and we wanted to try it out one night.
Finally, a single song to promote: "San Fransisco" by Scott McKenzie. This works as a miracle cure when I feel down or when I feel sad about the life I'm living. Somehow it gets a racing mind working properly again, while reminding me that there is a whole world out there that remains unseen for me. It tells me not to give up before my last resort has been tried.
This turned into a long post, which is a good thing for me. Thanks for making me sit back and think a bit for once.