Sun will be using their own SSDs later this year, citing that the move to SSD is inevitable and is just a question of how much time it will take. Their initial products will be performance-oriented, aimed mostly at those customers who have applications that put a high demand on I/O operations and other areas that SSDs excel in. After that initial adoption, Sun expects their more mainstream users to slowly follow suit.
Sun is taking a risk in backing SSDs, but not a very large one as they aren't abandoning their existing infrastructure. Choice is always good.