I understand where you are coming from. I will never use 100% in a dark room. I will use 50-65%.
Understand where you are coming from with the black screen issue, however..some people use the iPad as a digital portfolio, or watching movies, it is a factor at that point...though not for everyday Internet browsing.
The impact of the defect will vary based on usage. Initially it was not a concern, however..it is worsening.
That said I posted these as a sample comparison, not to have a debate about what is or is not acceptable, there's a huge thread for that already
Fwiw, my cheap Dell monitor, neither of my plasmas

, original ipad, my iPhone, nor a thinkpad have this issue, though my MacBook pro does very severely (well it just has an absolute crap screen). Or at least they may have 'light bleed' but it's uniform (ghostly overlay at 100% on iPhone 4), not casting strongly from one or two areas. The iPad 2 and transformer are the worse two devices of many in my house, but then maybe I've been lucky in choosing other screens, or paying more for some than many consumers these days...
It does seem the more we see LCD prices dropping, the worse quality control gets, which is unsurprising.