Car CD changers

Sony CDX-GT520
The Sony CDX-GT520 is a decent option for those wanting a reasonably priced stereo to play disc-based audio. While it does support HD Radio, it requires the connection of a clunky add-on module, which is almost more trouble than it's worth.
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-in, Audio line-out, Subwoofer output, System components control bus

Kenwood KDC-138
Specs: Radio / CD player, Audio line-in, Audio line-out

Kenwood KDCMP208 MP3/WMA/CD Receiver
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-in, Audio line-out

JVC KD G140 - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-in, Audio output

Kenwood KDC-X890
The Kenwood KDC X890 is a capable head unit that supports a broad range of audio formats. Voice indexing helps counteract awkward manual file selection, although the system's claims that it measures car performance are dubious.
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, USB, Audio line-in, Subwoofer output, Rear channel output, Front channel output

Sony CDX-GT120
Specs: Radio / CD player, Radio tuner, CD player, Audio line-in, Audio line-out

Sanyo FXCD-550 - radio / CD / cassette player
Specs: Radio / CD / cassette player, Radio tuner, CD player, Audio line-out

Sony CDX-R30M
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-out, Audio line-in, Remote control, System components control bus

Clarion CMD4A - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-out, Audio line-in

Dual XDV8125
Specs: Audio line-out, Composite video/audio input, Composite video output, Component video input, Navigation system input

Sony CDX-454RF
Specs: CD changer, None, CD changer, System components control bus, Audio line-out

Clarion DC 625 - CD changer
Specs: CD changer, None, CD changer, C-Bus, SPDIF output

PYLE Hydra Series PLCD16MRWB - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-out, Audio line-in, Remote control, Antenna

Kenwood DPX 301 - radio / CD / MP3 player
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-in, Audio line-out, System components control bus

Kenwood 50W x 4 MOSFET Apple iPod /Satellite Radio/HD Radio-Ready CD Deck

Clarion ProAudio DRZ9255 - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-in, SPDIF input, SPDIF output, Audio line-out, Ce NET

Boss MP3/CD Receiver-Detach Front

Pyramid CDR86DX - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-out

Eclipse CD4000 CD Player

Dual MXD55 - radio / CD player
Specs: Radio / CD player, Radio tuner, CD player, Audio line-out, Audio line-in

Kenwood KDC MP638U - radio / CD / MP3 player / digital player
Specs: Radio / CD / MP3 player / digital player, Radio tuner, CD / MP3 player, Rear channel output, Front channel output, Audio line-out, Audio line-in, USB, System components control bus

Kenwood eXcelon KDC X590 - radio / CD / MP3 player / digital player
Specs: Radio / CD / MP3 player / digital player, Radio tuner, CD / MP3 player, Front channel output, Rear channel output, Subwoofer output, USB, System components control bus

Pioneer CDX P1280 - CD changer
Specs: CD changer, None, CD changer, System components control bus

Sony CDX-GT500
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-out, Remote control, System components control bus, Subwoofer output

Clarion DXZ 665MP - radio / CD / MP3 player
Specs: Radio / CD / MP3 player, Radio tuner, CD / MP3 player, Audio line-out, Audio line-in, System components control bus