Yet another Gartner analyst says BOTH to java vs. .Net

.NET vs. Java: No Easy Answers: "Choose Both
Despite any attempts to select either platform as a 'strategic' de facto choice, virtually all large development organizations will ultimately have both....It's entirely unrealistic to assume a large national or multinational company will have all Java or all Microsoft technology. For that matter, legacy platforms such as Cobol will also remain entrenched for many years to come.
In these cases the 'us vs. them' battle must be tempered with a higher-level integration strategy. Although there are no easy answers to this problem, technology such as Web services standards are beginning to emerge and will allow better integration and interoperability between the platforms in the future"