I understand that in some cases managed code can run slower or require more memory. Still, I was disappointed that Microsoft (some time ago, apparently) removed .Net code from beta builds of Window Vista.
As a Linux enthusiast (yes, I am posting from Ubuntu right now :-) I would also like to see managed code in the Linux kernel and surrounding utilities. I would be happy to take a performance hit to improve security (just getting rid of buffer overflow errors would be huge) and reliability.
I believe that Java Hotspot technology, or something similar would work just fine. I am not a .Net expert, but I would imagine that they use something like hotspot, use ephemeral(or generational) garbage collection, etc. I linked to an article the other day that showed that in some cases managed memory can be faster than C mallocs.
Anyway, I sold my Microsoft stock last year (I was very irritated with them for not supporting open document formats and decided that I simply did not want to own their stock) but as a sometimes Window user, I was enthusiastic about their using managed code in Vista.
PS. the best programming and computing environment I ever used was in the 1980s: my Xerox 1108 Lisp Machine - used "managed code", never had problems like buffer overruns, and was extremely reliable. Then performance was OK, even with relatively slow computer hardware (this was 20 years ago!)