CORBA
I have been interested in CORBA right from the beginning
(i.e. when the standard was so embryonic, CORBA would not even
interoperate with itself!). Despite the complexity of the standard,
I still think CORBA has a lot to offer. I have used several ORBs, some
open source, some proprietary. My favourite used to be MICO but unfortunately
the support for multithreading is still not finished so
TAO (the ACE ORB) is now the winner. I have also looked at
JacORB by Gerald Brose.
The best proprietary ORB (IMO) still seems to be Orbix from IONA
(now owned by Progress).
For those interested in CORBA I recommend heading over to
the web site of
Ciaran McHale, a former IONA
consultant whom I have worked with before. He has a free book there which
I think provides a great practical introduction to programming
with CORBA.