Athenian, if you are open to getting certified, becoming an Oracle Database Administrator is an extremely lucrative job.
Oracle Database administrator Salaries - Free Salary Search | Indeed.com

As far as Linux vs. windows, it is pretty much a wash.

Linux avereges slightly higher, but both the entry level position and the top pay are lower for Linux.
Windows System Administrator Salaries - Free Salary Search | Indeed.com
Linux System Administrator Salaries - Free Salary Search | Indeed.com

If you are willing to learn CSS, XML, XSLT, and SQL on top of your HTML skills, you can get into Web Design.
Web Design Salaries - Free Salary Search | Indeed.com
If you are willing to learn AJAX on top of that:
Web Designer, Web Designer AJAX Salaries - Free Salary Search | Indeed.com

If you sharpen your C++ skills, there are good opportunities for you as well.
C++ programmer Salaries - Free Salary Search | Indeed.com
Java is very similar to C++ (and easier to program in, IME):
Java Programmer Salaries - Free Salary Search | Indeed.com

Visual Basic Programmers get paid a little less:
Visual Basic Programmer Salaries - Free Salary Search | Indeed.com

Becoming a computer technician seem pretty easy, but the pay isn't that good:
Computer Technician Salaries - Free Salary Search | Indeed.com
Though System Configuration pays more:
System configuration Salaries - Free Salary Search | Indeed.com

It takes a lot of training, but if you want to get into my field, the pay is very good:
Chip Design Salaries - Free Salary Search | Indeed.com
Integrated Circuit Design Salaries - Free Salary Search | Indeed.com
FPGA Design Salaries - Free Salary Search | Indeed.com
Though, you can get in with less training if you do Mask Design:
Mask Design Salaries - Free Salary Search | Indeed.com

I would work on getting some sort of certification, it'll help a lot
CCNA Salaries - Free Salary Search | Indeed.com
CCNP Salaries - Free Salary Search | Indeed.com
MCSP Salaries - Free Salary Search | Indeed.com
MCSE Salaries - Free Salary Search | Indeed.com

Those are the salaries, but ultimately it is what you are interested in that matters.

I am giving up a rather lucrative job (see above) for something I am more interested in right now, but pays a lot less:
Physics Lecturer Salaries - Free Salary Search | Indeed.com
Physics Post Doctorate Salaries - Free Salary Search | Indeed.com