Strange timing.
Here is one of my favorite microwave magnet projects, Joseph WXYZSCIENCE's car alt,
http://www.fieldlines.com/story/2007/7/4/225522/5838
The transformer coils are worth quite a bit at the scrap yard if they are copper, but I wouldn't expend the effort to try reusing it as wire.
The transformer lamination pieces are worth quite a bit as parts (single rotor with laminations), or tools (in the process of gluing down magnets close together) for my tinkering.
Grind off the welds and the disassembly is a lot easier.
A handful of strange switches, fuse holders, bulb sockets, and short scrap wire is handy sometimes.
The aluminum layers between the magnets can be used for heat sinks. Or scrap (take apart a dozen microwaves anyway, and the scrap value adds up pretty fast).
I even saved a few cases for the sheet metal.
I never gutted a microwave that did not have a resistor across the big caps.
It still makes me a bit jittery, but I never saw one that would not be safe if it was unplugged in for a week.
G-