Great Apps to have are:
Screen Filter -> Brightness Control
Aldiko 2.0 -> General reading and DRM capable
Dolphin Mini (experienced problems with Dolphin HD, but worth a try) -> Browser
Wallpapers
K-9 -> Mail
Documents to go -> Reader for *.doc, *.xls and *.pps
Battery Calibration -> Useful after reflashing to get max battery life (needs root)
Launcher Pro
Titanium Backup -> Save before and restore after flashing (root)
NetQin -> Anti-virus, -spy, -malware
And of course
Kindle,
Kobo,
Youtube
Waiting eagerly