I bought into the hype about the Dark Tower series and read the first three books.  I completely understand the compulsion to finish a book that you've started - I keep thinking 'It's GOT to get better' and then there's only 100 pages left or so, and so I might as well finish it - only to find it just plain sucked. 

I read the Da Vinci Code and recently finished Angels and Demons - they were strictly ok.  I've been reading the 911 Commission Report off and on since it came out apparently because I'm a glutton for punishment.  I would recommend the The Devil in the White City by Erik Larson - it's about the architect of the 1893 World's Fair in Chicago.  I also enjoyed Dress Your Family in Corduroy and Denim as well as Me Talk Pretty One Day by David Sedaris.

I like the Harry Potter series even though my 6 year old boy doesn't.  He's much more into Lemony Snicket.