Thanks for your reply Michael,
I went through each compression type using that basic syntax, changing only the output file name and the string passed through the tiff_compression keyword; FYI when specifying JPEG compression I received the error: PageLayoutObject: Error in executing ExportToTiff.
All other compression types (including 'none') resulted in a small, corrupted file ( 'NONE','LZW','DEFLATE' : 4K, 6K, 120K vs. 50 MB for successful 'NONE'). I then remembered that maybe I should try exporting directly from ArcMap, which also failed. This reminded me of a problem I've been having on my main workstation with 9.3. On both that and this secondary laptop I'm running windows on a Parallels VM under OS X. The laptop is running XP under OS 10.6.4 while the workstation is running Windows 7 32-bit under 10.6.3, parallels version is the same at build 5.0.9344. At some point in the last few months the workstation suddenly stopped behaving well when trying to create featureclasses on a network shared based on an OS X-based folder.
As it stands, if I try to write to the c: drive ExportToTiff() works for both ArcMap and Arcpy. Oddly, though, ExportToPDF(), ExportToJPEG(), and ExportToAI() all work even when writing to an OS X folder. I'll have to investigate this further given time, but for now at least I know I can batch our exports through Python.
Cheers,
Kelly Crowell