Clockwork Mod Recovery
Root Checker
Astro File Manager
Rom Manager
Set Cpu
Thor Kernel (to overclock to 1.5ghz)
Nobars (to turn off cell usage and increase battery life) even though its a non 3g version
Acer Recovery Installer
USB Mount All - Supports FAT32 and NTFS hard drives
Root Explorer
tTorrent
File Manager HD
Olive Office Premium
Buzz Player
Most of these are great for tablets or phones.
As for custom roms I havent used any yet.
Taboonay looks like the rom I will try out, gets some good write ups