OK I’ve experienced codec hell on Windows, and while the Mac is much much better, as soon as you do something off the beaten path, well it gets complicated. I wanted to use some clips from a commercial DVD in a presentation (gasp!) and after wandering around the forums for a while, I bought the Apple MPEG2 codec and then used MPEG Clipstream to rip the entire DVDs. Then I exported to Quicktime and slurped the movie into iMovie. From there I found the clips I needed, created some small projects, and then exported to several formats for PC viewing — and the target PC only has WMP and I can’t change the software load on it. MPEG4 — too much compression, looked terrible. Various QT formats — some look ok but none would play in WMP. Finally settled on AVI as the format — first used the default cinepack compressor with default settings — worked fine but too much compression! Re-cinepacked at the highest quality settings and looked/worked ok. and then redid as DV-NTSC which also looks/works good but is pretty big.
This would all be so much easier if Apple/MSFT could agree on some basic codec loads for their machines.