Found this over at the evo forum by evokings so i took it and made it work for us.
This will most likely prevent problems with installing ROMS. Please Wipe before reporting bugs caused by the User(This means us!)
It will wipe:
Data (Dalvik-cache is included in Data)
You choose what you want to wipe......
This is great for flashing ROMS. If you are using a custom recovery and it has an "update.zip" option, for quicker access just rename the zip to "update.zip"
WIPE--ALL.zip--> Wipes Boot, System, Cache, & Data
WIPE--System_Data_Cache.zip--> Wipes System, Data, Cache
WIPE--Cache_Dalvik-cache.zip--> Wipes Cache & Dalvik-cache
Thank evokings from evo