I mentioned this in Gamer9430's thread on the subject, but I have some specific use cases where doing things on a relatively new Intel Mac is painful enough, much less trying to do them on a PPC.
I use Endnote, a citation management program, a lot with my work and school documents. I'm currently working on something with 100 pages and 120+ citations, and it takes Endnote about a minute to insert a citation on my i5 MBP. Word is a huge memory hog with this type of document, and I've had it crash several times. I started writing it on my Quicksilver, but some of the stuff was just eating up time that I really couldn't use.
If Endnote and Word weren't the half baked pieces of garbage that they are, I could probably still by with only PPC. Truth be told, with something that's a few pages long and has a handful of citations(if any) PPC works fine. For heavier duty stuff, though, I'm afraid I'm stuck with Intel.
Hopefully, this will be the last thing I have to do for a while that involves a document of that length and complexity, and I can go back to PPC for most of my work. For the time being, though, I'm afraid I'm glued to Intel
(typed from my dual core G5)