Is de always pronounced "dom"?
With the new voice I'm having to get used to the pronunciation of "de" as "dom". (At least it's very helpful that I can no longer confuse det/de) How often is this pronounced "dom" in Swedish? Is it like "och" where you usually say "o" but it also has a stressed form "ok", or is it something that only meticulous people pronounce as "de", or is it something that literally nobody ever pronounces as "de"?
Also, is this all the same in sentences like "de stora stader" - the big cities, where it acts like "the" in English?
Yup, agree with Zmrzlina, I've always heard it said as "dom" (lived in Sweden for 4 years).
I speak more with books than with people, and when I speak I sometimes accidentally say "de", whereupon people give me funny looks, as it sounds very formal (though this impression is actually mistaken).
It's always "dom".
A few minor dialects diverge on this, but that's nothing to concern yourself with when learning Swedish.