Advanced Configuration Tool 3.0 is now available, a lot of research and disassembling to give you access to more than 200 tweaks, this new version is fully compatible with HTC Diamond. It includes TouchFLO 3D customization and supports TouchFLO 3D soft-keys mapping.

Features - too many to mention - but I recommend these:

Phone - Fast Sleep during call: Disabled

Miscellaneous - Security warning: Disabled

For full list of tweaks: HTC Touch Diamond tweaks

Also see: Diamond TouchFlo3D - Improve performance and Custom tweaks

Full Details and download - from official website

xda-developer forum details