The linux kernel for sure. Servers and smart phones. It may not conquer the business desktop soon, but the desktop is a smaller piece of the pie every year.
Relational databases will be around forever. The nature of data does not change. Relational data will always be a good fit for an RDBMS.
I think skill in low level languages like C will have less market share in the job market, but always needed. It could be a lucky financial boon for people who have these skills, as they will be a rare commodity.