The Lyra is a good light, if you like *bright* lights. I don't, so I'm using an m-Edge eLuminator2 tucked into the back of the Industriell Easel cover (see attachment). I prefer the m-edge low setting.
I've tried every one of the booklights at Borders and B&N - the handful that clip directly to the Nook require coin batteries or have excessively large clips that are too large for the Nook's bezel. And most are even brighter than the Lyra, as they have 2 or even 3 LEDs because they are designed to cover both pages of p-books.
There is also the
Belkin Clip-On, which has two light settings. I'm thinking about trying that with my Opus.
Some people like the
Kandle, others complain that it doesn't provide good coverage to the bottom of a 6" screen.
I wish Octovo would make a
Solis for the Nook. It looks like it is a slick light.