Lots of stuff in the car at the moment...

Helmet: Betty - I've almost burned a hole through this disc because I've listened to it so many times. If I was forced to only keep one CD in my entire collection, this would be it.
Helmet: Aftertaste - The last CD from the Hamilton/Stanier/Bogdan lineup. I don't think it's their best, but there are a lot of great moments.
Soul Coughing: El Oso - Their last studio CD. I got to see them at Roy Wilkins after they released this CD. They put on an excellent show.
Soul Coughing: Ruby Vroom - It's good.
Fugazi: Repeater - It's good.
The Melvins: The Maggot - My favorite Melvins disc, and maybe their heaviest. Some signature Melvins riffs. Perhaps the best part about the CD is that each song is split right down the middle into two tracks.
The Melvins: The Bootlicker - While The Maggot goes to 11, this one goes to about 5. You know it's the Melvins when you listen to it, but it's toned down with clean guitars. Some great tunes. I saw them perform some of these tunes live, and they play them at 11.
311 The "Blue" album - A lot of die-hard 311 fans dislike this one because it really broadened their fan base. So what. It's a straight-ahead in-your-face rocker that kicks ass.
311: Music - The 311 debut. The production is a little weird in my opinion, but it's a debut. This one is full of 311 classics and it's interesting to hear how broad their style was even with their debut. Plenty of rock/metal, hip-hop, reggae and dancehall flavors in all of these tunes.
311: Soundsystem - I got to see 311 a 2nd time while they toured with this album. Not their greatest but has some good stuff.
The Mars Volta: Frances the Mute - I really haven't gotten into this one yet even after a couple of listens. It's definately an album you have to listen to. A lot of great playing, but it's tough to really get attached to any of the songs. Kind of like orchestral music: I used to be big on a lot of orchestral works - especially Rachmaninoff, Shostakovich, Samuel Barber, and Ravel. But after I got a job and life got busy I stopped listening to it. It takes time and effort to get into that stuff because the music takes so much longer to develop and there are more ideas to get across. Now I just want a quick fix when I turn on the CD player in the car. :)
Radiohead: Hail to the Thief - I think this one is their most diverse. Lot of different sounds from acoustic to electronic. This album captures a lot of their songwriting and performing talent, but I like Kid A, Amnesiac, and The Bends much better.
Radiohead: OK Computer - It's good too.
Tool: Aenima - What needs to be said? It's Tool.
Meshuggah: Nothing - I saw them open for Tool a while back. They put on an incredible performance. A bunch of Scandanavian guys wearing hockey sweaters unleashing a severely complex wall of brute sound.