You shouldn't worry too much about the value of what you read. I've just finished The Girl with the Dragon Tattoo
. It was very entertaining, and it was also disturbing in some passages. It's not great literature. Before that, i had read Blue Mars
, the third volume in a wonderful trilogy. I think it's some of the best science fiction ever written--but more for the adherence to genuine science than anything else--it's not undying prose. Light fiction might be the best bet for you right now. You could read a few pages, and no big deal if you set it down and don't pick it up again until the next day, or the next week. When your children get older, you might have more time for reading. The fact of reading is more important than any arbitrary assignment of worth to what you are reading.