I use all <tt> for my damage abilities, and all <t> for my heals. I never use mouseover, and I'll explain why.

I've found it is very powerful to direct my faery's heals where I want them to go, yet you cannot do a mouseover macro for the pet. This way, I have the tank targeted, and when I need to DPS I just hit one of my macros to automatically hit whatever he is hitting. Very useful to not have to stop and re-target to use Energy Drain or to drop a Bio on an enemy. I can always direct embrace at whoever I am targeting.