Originally Posted by Phasers

Assuming one to one on all transfers (if you have the sapphire preferred card for example), then this seems to be your best bet:

Hyatt Gold Passport converts to (starting) 100,000
* American AAdvantage (at a ratio of 50000:25000) Total: 50,000

OR

Hyatt Gold Passport converts to (starting) 100,000
* American AAdvantage (at a ratio of 2.5:1) Total: 40,000

...depending on how many points you have.

Everything else has a severe devaluation or uses Amtrak (or both).

edit: depending on how far you are from LT gold, 2:1 devaluation might or might not be worth it to you.