I think initially I was just going to reread The Crippled God. When I finished it, I couldn't think of anything else to read, so I grabbed Dust of Dreams. After that book I think I just decided I'd go for it and read the whole thing in reverse order.
My brother, and a few of our friends are working on the series, though none of them has made it past Reaper's Gale yet (I don't think, anyhow). They've been working on the series for a few years, and talk about "not having time to read," or being "distracted by new characters, losing interest," that type of stuff.
So I think part of the backwards reread was to show them what pussies they are for not being able to read an epic fantasy series. Another part of it is being able to actually say I know the story forwards and backwards. Kind of embarrassing, but it is what it is.