I read a lot of omnibus editions.
Three book series and the like tend to be handier for shelving as a single volume, and I usually fall prey to the nice new covers while wandering through the bookstore, so I buy them.
They're great, until you get home and are reading one in bed, where, let's be honest, most reading is done. You crack open your mammoth tome, wriggle into the pillow, and find yourself spending the next half-hour trying to discover a comfortble way to hold eight pounds of wood pulp in a position that doesn't kill your wrist, smother you or mangle oversized trade pages. If you are sleeping next to someone else, they'll likely not be impressed by the light or the constant crackling of paper and mumbled curses.
I like the smell and feel of a book. I like it a lot. But I'm beginning to think the e-reader is edging it with its sheer convenience.
And they tend to be under a pound.