Sheesh... the list is enormous.
MY MUST HAVES:
HTCWiFiRouter
Google Maps
Q Inbox Extender
Xda-Developers HDWallS
Chainfire TP2 AppUnlock
CO7 VZW Logo Remove
Hoots TD2 No Top Curtain
silverkorn VZW TP2 Clear Flip Clock
psShutXP Power Key
PPCSoft psShutXP TouchPro2 Pimp'd
MrGC YouTube Black
TiR Team Opal Volume Control
TSOWEN Taskbar Pimp'd by CMYLXGO
no2chem 1% Battery Driver
SSK TP@ Dynamic Resource Proxy
Skyfire Browser (For FLASH)
MightyMike Signal Strength Level
A_C S2U2
CMYLXGO's EnergyROM 3.0 S2U2 Theme
MS .NET CF 3.5
All of these things have made my TP2 SO MUCH more attractive and fun to use than it was stock. I can't even remember what it looked like stock because it is so different now. Cleaner, crisper, more detailed.
And just so you know, you can always remove a cab that you install. Just go to All Settings>System>Remove Programs.
To install any CAB, just copy it to your phone or SD card and go into the file explorer, find it, and open it. It automatically installs from there. Also, be sure to reboot the phone to make sure changes take effect.
EDIT: Here's a screenshot of my home screen