I agree some books in the OT have little contemporary information in comparison to the NT, but I wouldn't ever say it's not necessary to read them.
I've found that if you read books like the Kings and Leviticus just because you should, you don't get much out of it at all. But when you read them because you want to hear something from God, knowing that He kept them in the Bible for a reason, you get so much more. The OT backs up the NT. It helps explain why they did some thing or said some things in the NT. And I'm talking about every book in the OT does this, even Leviticus, of which is most difficult for me to get through. The Kings were my favorites of the "boring" collection. SOOOO much information packed in those books and still it leaves out so much.
I challenge anyone to read the "boring" books with a different perspective. You don't know what kind of blessings you're missing.