GreenHills AdaMULTI, ICCAda, Janus/Ada, PTC ObjectAda and ApexAda, SCORE from DDC-I, AdaCore GNATPro of course
Just saw your last comment. Then FSF GNAT is your only choice
The good news is that it's prob the best one
How has the idea of Ada been received so far?
<Oops! just to clarify, 4 of the compilers I listed are Ada2005 as well: ICCAda, ObjectAda, ApexAda, and GNATPro)