There's a great piece out by InfoWorld's Eric Knorr on the impending resurgence of the ultimate SOA machine: the mainframe. Big Iron is constantly given up for dead, yet IBM is reporting record sales, especially the ones that run Linux.
A very short history -- mainframes were accessed by "green screen" terminals that were eventually emulated on PCs, then through browsers. Now, Web services components capture mainframe-based processes, while leveraging Big Iron as a data repository. Web services/SOA will extend mainframe investments well into the future, and mainframes will provide reliability and scalability to Web services/SOA. That's pretty good synergy.