While doing some preliminary research on a CS2 C# textbook, I found a great paper comparing Java and C# for use in CS1 and CS2 courses.
I was impressed with how well C# faired against Java considering Java is quite popular in the academic world. And one of the authors points against C# – its lack of cross/multi-platform support – is addressed by the exciting Mono project.
(In case you didn’t know, I’m an adjunct professor at Greenville College. I taught CIS210 in the Fall (a CS1 class) and will be teaching CIS211 (CS2) in the Spring.)