what transmission to use with new hemi 5.7

Ok, so there is litterally hundreds of threads on the net about this. But I am still confused, overwhelmed really..

I ultimately want a manual tranny, so I may decide to hold off on doing anything im about to talk about.

As it sits now, I have both a 904 and a 727. My hemi dart will see highway driving, so I want an over drive. From what I read this will drop that RPM at high speeds.
I have read about OD addons, and even a 518 tranny...but then there is computer verse not computer controled, etc etc.

I am lost.

If I got manualy, its gonna be work as I am gonna try to stuff in a t56.
HOWEVER, if i did decided to stay auto, what would be best?
Take my 727 and get it upgraded (i have read it may need to be beefed up for the hemi), and then add an OD?
Get a 518?
then there is even the 545RFE, which can be controlled by the ecm..helps with throttle kickdown linkage issue.

Any directions or help narrowing this down, would be greatly appreciated.