On Books I Never Finished Reading

I know there are a lot of purists out there that would insist that, in order to review a book, one must FINISH the book first. Quite obviously, based on my videos and textual reviews, I don't agree. I believe that one should finish the book if, and only if, it's actually interesting and actually compels one to continue on.
Having said that, it should be noted that I always attempt to finish a book before I finish a review. In some cases, however, this proves impossible. It's just how I am. I'll start reading a book, get halfway through, and declare it uninteresting and on my bookshelf (or iPad) it'll sit until I go to make room for new purchases.
Harry Potter and the Deathly Hallows was one such book. I got it on its release date and devoured PRECISELY half of it in about three hours, went to bed, woke up, and stuck it on the bookshelf after trying to read about four more pages and finding it completely uninteresting to me. And I had been enthralled just a few hours before.
Unfortunately, I know that I will be reading the entire books for at least the next five reviews.
But I also don't plan to hold back on the next five reviews.
Should start preliminary script writing for the Twilight review here in the next few hours. I anticipate this video to be a minimum of 15 minutes (script will be posted here for those too lazy to watch the video on youtube. Video may also be embedded here, haven't decided.) to a possible maximum of 45 minutes, depending on how in-depth I decide to get with my attack review