This is an interesting observation. I've been writing code for about twenty years, and using some form of syntax highlighting for a little over ten of those years. I change the colors in vim (and geany, my other IDE-du-jour) to match function names with a bold blue and variables with a bold, dark red. These colors are the ones I definitely change every time on a new install/machine/whatever. I can see exactly what we would think with the color-syntax association, but it's not quite the same as my synesthesia. Like, when I type out a function definition, I don't have a bold blue "mindset" while doing it. However, when I type the word Wednesday in that context, there's a thick undercurrent consisting of the "softish bright red". It's really, really hard to explain, but there is a difference for me.

Oh well, it's no surprise, really. Visual cortex is vast and depending on which areas/levels take part very different effects may be present.

Yes certainly, synesthesia has many different forms. From what I understand -- and I could be completely off, but this is just information I've tried to collect since I finally had a word for the condition -- the word-color synesthesia thing is pretty common. Sound-color exists, but it's pretty uncommon. Among many, many different combinations. One of my friends has confided in me that she feels different temperatures with different words. I hadn't heard of that before, but I don't doubt it. There were some scientists who did MRI work on synesthetes and found that it basically amounts to functional crossovers in the brain between the affected areas.