If you don't mind sharing what kind of stuff do you do (or rather, what do you want to do)? Work for banks/finance? Technology startups? Academia (ie. research type stuff?)?
Also what general aspect of computer science interests you most?
This kind of stuff IMO has an influence on what is the best technology stack to invest time in.
Perhaps we should take this discussion elsewhere but I enjoy answering / sharing. First and foremost I LOVE to build things that people can REALLY use - and make a good living doing it. I've done considerable work in banking/finance and manufacturing and device control systems; almost exclusively "Line of business (LOB)" applications. Not into academic or research stuff unless it's in support of building something people can REALLY use.
That said, I have opportunities to build web-based applications and I am - at the moment - looking for a full-stack alternative to the Windows / SQL Server / ASP.Net suite that currently "puts food on my table". It seems noteworthy that customers with whom I interact are overwhelmingly and emphatically opposed to cloud solutions. Their web needs are typically customer facing "bolt-ons" that expose select internal data they simply will not trust to the cloud (I sense this that is softening a bit but for now it's my reality).
So, again, I've got CentOS / Oracle / JEE (still wavering a bit on Oracle but shying away from MySQL). It's the higher-level Web Application framework I am finding hard to sort out.
Thanks for asking