There are a bunch of recent camera firmware updates that should be mentioned:

Canon EOS-50D: Fixes vertical banding when using sRAW1 setting; adds support for 270EX Speedlite; gives more specific error codes
Canon EOS Rebel XS / XSi - adds support for 270EX Speedlite
Nikon D40 / D40x - adds support for EN-EL9a battery
Panasonic Lumix DMC-FS15 - improves image quality
Panasonic Lumix DMC-TS1/FT1 - allows viewing of 720p movies recorded by DMC-GH1; improves playback mode image quality
Panasonic Lumix DMC-ZS1/TZ6 - focusing noise in Quick AF mode reduced; improves playback image quality
Panasonic Lumix DMC-ZS3/TZ7 - allows viewing of 720p movies recorded by DMC-GH1; reduces focusing noise in Quick AF mode
Pentax K20D - improves Shake Reduction
Ricoh CX1 - Fixed bugs in continuous shooting and focus bracketing modes; improved compliance with Multi-Picture format
Ricoh GR Digital II - Adds manual flash strength adjustment, flash sync timing, number of photos taken per day; fixed bugs in playback mode