I had the same situation. I worked for in a hybrid software engineering/operations role for a large Internet firm, while studying part-time. It was a great and challenging position, not just due to its content (how do you deal with running tens of thousands of nodes in clusters distributed throughout the world?) but the people and the environment (it was one of the few places where you could find people in an operations team hacking OCaml).
Ultimately, I was found by a start-up and left, seeing greater responsibility and compensation. Six month in, I started looking around. The lack of mental stimulation scared and de-motivated me. I switched jobs to a non-web-centric software engineering role. It felt "scary" ("job hopping" as the country headed into the recession?), but it was the right choice.
The risk is thus: if you're bright, it's very easy to become good at most anything. Some fields (systems administration, web development) can be fun (given the right environment, e.g. the operations team I've described) and are always in high demand. None the less, if you become good at something you don't ultimately find challenging and worth-while it can be a risk further down on.
Have you consider going into scientific software development? Both your web development background (the web is the user interface these days) and your scientific education will be of help. You might take a paycut, you may not have the flexible hours, but the job might provide both the content and the environment (i.e. the people) that will keep you sharp.
Scientific software development is something I've considered, and it's becoming more and more appealing as a possible alternative to me. However, I'm not very familiar with the current players in that industry. Do you know of any companies that specialize in this?
Where are you geographically? Why not work for a bio-tech or a physics related firm? They need good coders.
If you're in San Francisco Bay Area (or want to be in Bay Area, perhaps you could finish your degree at Stanford/UCSC/SJSU/SFSU/SCU?) and know (or would like to learn) Perl, C (and some Java), there's a really interested job opening I found on a local Perl mailing list. It's related to bioinformatics, which is different from your background but nonetheless would be something that "keep you sharp".
Another option that's even more closely related to what you're doing now is perhaps picking up machine learning/NLP/information retrieval. It's very heavy on (mostly continous) mathematics/numerical analysis. I have a feeling somewhere that you're probably pretty good with dealing with sparse matrices, graphs and the like. There's tons of Internet/e-commerce companies doing more and more with that.
Ultimately, I was found by a start-up and left, seeing greater responsibility and compensation. Six month in, I started looking around. The lack of mental stimulation scared and de-motivated me. I switched jobs to a non-web-centric software engineering role. It felt "scary" ("job hopping" as the country headed into the recession?), but it was the right choice.
The risk is thus: if you're bright, it's very easy to become good at most anything. Some fields (systems administration, web development) can be fun (given the right environment, e.g. the operations team I've described) and are always in high demand. None the less, if you become good at something you don't ultimately find challenging and worth-while it can be a risk further down on.
Have you consider going into scientific software development? Both your web development background (the web is the user interface these days) and your scientific education will be of help. You might take a paycut, you may not have the flexible hours, but the job might provide both the content and the environment (i.e. the people) that will keep you sharp.