It's not the new hotness, and not really sexy, but if you care about employability, it's hard not to recommend Java. Between enterprise backend web services, Android, and to a lesser extent desktop apps, there will be plenty of Java jobs over the next decade.

The nice thing about 'enterprise' companies is they tend to have a lot of money, and will be around for awhile, needing their code built/maintained. Same can't be said for most startups.

Python/Django or Ruby/Rails is another solid choice, but people don't realize how rare these tech stacks are outside of the SF Bay Area and NY. They got nothing on Java. I would say it's even easier to find .NET employment relative to the tech stacks commonly talked about on HN. For instance, in the midwest, companies will throw fistfuls of money at .NET devs as they are in high demand and low supply at the moment.

You are asking about an 'interesting job' though... at the end of the day only you can decide what you find interesting.