Funnily enough they also fall in the same categories...
The New Romance
The book/knitting project that I only just got my hands on, but which I just couldn't stop myself from starting right away. My parents gave me "The Casual Vacancy" for my birthday, and of course I had to start that very same evening even though I already had a pile of other books on the go. Similarly, I recently started a $5 Paris KAL together with Pandabearofdoom on Ravelry, and now that seems to be the only thing I want to knit! I've come just below the armpits now, although I'm slightly worried it'll turn out to be too small (I'm knitting the medium size which usually fits, but it seems... small). I'm not entirely sure though, so I've added a life line so that I can easily rip back if it turns out to be necessary.
The Long Haul
The book/knitting project that seems to go on forever but which you're sure will be well worth the effort once you're done. "Giants of the Fall" is a great read and the Piano Scarf a delight to knit, but both show so little progress from each sitting that I hardly feel like I'm getting anywhere.
That does not mean I'm about to give up on either though! I'm in for the long haul :)
The book/knitting project that I could really finish if I just sat down and put my mind to it for a couple of hours. I only have 200 pages to go of "Fire Study" and my classic gloves is only missing half of the left glove. I would have been further if I hadn't made a rookie mistake last week. I was happily knitting along for 10 rounds after the cuff when I discovered that, DOH! I was knitting the right-hand glove again rather than switching to the left. I promptly ripped out the 10 rounds, and then started knitting the hand again... only to realize that since the cuff is completely symmetrical, I could just have moved the 'start of the round' 10 stitches to the right, and I'd have been right on track again. You live, you learn... I really should finish it though. It's almost glove-cold in the mornings now.
The book/knitting project where I'm deliberately limiting myself to small doses, because I just don't want it to finish! "Happier at Home" is such a book and the Haruni such a project. Both things are doled out as small treats.