Originally Posted by TongueTied
You actually have it in 2 places. First, on the home screen, but as has been mentioned if you purchase a new book, it will push the 5th most recent read off your home screen. Second, if you go to Library, and hit "by title" then choose recent reads, it sorts your books by last date/time opened. That shows only 5 books per page, but the screen really isn't big enough for any more.
You can change the display to show more than 5 books in the library view by clicking on the icon in the lower left. I can't remember exactly what it looks like and I don't have my Touch handy to take a look.