I assembled an overview with the current state-of-the-art eReader, for decision making. The information are mainly taken from the product websites, spec sheets  and wikipedia.com.

Updated Nov. 2009

Amazon Kindle 2 Txtr Sony PRS-600 Cybook Opus
Price $259 (179€) $463 (319€) $299.99 (207€) $250 (173€)
Screen Size (in) 6 6 6 5
Resolution 800 x 600 800 x 600 800 x600 800 x600
Color Depth (Grayscale) 4Bit (16) 4Bit (16) 3Bit (6) 3Bit (6)
DPI / PPI 166.7 166.7 166.7 200
Touch Display No No Yes No
Weight 289g 300g 286g 150g
Height (mm) 203 151 3Bit (6) 151
Width (mm) 135 131 122 108
Depth (mm) 76 12 10.1 10
Internal Memory 2GB 64MB 512MB 1GB
Extandable Memory No MicroSD (8 GB) MicroSD ,Stick Pro Duo MicroSD
Native Reading Formats Azw, Txt, MOBI (no DRM) PDF,
HTML, Office, ePub, ?		 ePub (DRM), PDF
(DRM), BBeB (DRM), JPEG, PNG, GIF, BMP, TXT, RTF		 ePub (no DRM),
PDF (no DRM), HTML, TXT, JPG,
GIF, PNG
Native Audio Formats Audible, MP3 None MP3,
AAC		 None
USB Yes Yes Yes Yes
Wi-Fi No 802.11 b/g No No
3G EVDO Modem (Whispernet) Yes No No
Bluetooth No Yes No No
NFC 2.4GHz No Yes No No
Battery Capacity (mAh) 1530 2500 ? 1000
Battery Replacable No ? No Yes
CPU Freescale ARM-11 Freescale ARM-11 Freescale ARM-11 Samsung S3C2440
ARM920T
CPU Speed (MHz) 532 532 532 400
RAM Memory (MB) 32 64 128 32
Operating System Linux Linux Linux Linux
G-Sensor (Rotation) No Yes Yes Yes
Speakers Yes No No No
Audio Jack Yes No Yes None