OK...here's the story:
I got the best results exporting from illustrator to photoshop. With this file, I tried the following:
1) opening it in keynote..then exporting as a powerpoint file. The problem is, in both keynote and the exported file, there seems to be a noticable bleaching of color transparencies. I'm guessing these are introduced during importing. White transparencies ARE fine, I haven't checked black or grays yet.
2)opening the file in photoshop, then saving as a .gif file. This worked pretty well up until the time I tried it with color transparencies. I don't know if it was my settings or the nature of the file format, but it slaughtered the color transparencies. I had a plate of 3 intersecting color discs, and it basically got rid of all non-overlapping sections. Strange.
3) opening the file in photoshop, then saving as a .png file. BINGO!!! This worked PERFECTLY. Handled all the images I tried, did great with color transparencies, was recognized by both keynote and powerpoint natively, and exported from keynote to powerpoint flawlessly to boot. And the file sizes are respectable, too. I think this will be my export option of choice for the near future.
One quick note...Keynote was able to import flash files in addition to photoshop documents...powerpoint could not open either.
Anyways, thanks for the info...now if I could only find one that worked well with iMovie, too
thanks,
-John