Figured I would start a thread on what people are finding using the mystic forge. Not necessarily crafting but it is close.
You can only combine like color items in the forge. You get a better item through combining 4 other items. However, the item you make won't necessarily be an item you can use.
One "recipe" posted on MMO that seems like a smart move. I don't think this is an exploit but if someone thinks it is please edit my post and let others know.
1 x Master's Salvage Kit
1 x Journeyman's Salvage kit
1 x Fine Salvage kit
3 x Mystic Forge Stone
= a 250 use Mystic Salvage kit