I understand we as adults and parents have a lot on our plates. Whether it's paying the bills, cleaning the house, doing the laundry or sometimes even having to do some work at home after hours. But you should never, ever, ever say no to your child when they ask you to read to them. This is one of those times where it's just you and him/her (or them) and they are totally fixated on what you are saying and showing them. You have their undivided attention for around 10 minutes and they love it. That is precious time you should never turn down. As they get older it also gives you a chance to practice the alphabet, spelling and reading.
Plus, it gives you a chance to re-live all the books that hopefully you read as a kid. Where The Wild Things Are (aside from that kid being a spoiled brat) was one of my favorite books as a kid. Miss Nelson is Missing which they are starting to enjoy. Not to mention all the Dr. Seuss books. But there are many good new books too. Giraffe's Can't Dance, Walter the Farting Dog and the Pigeon books by Mo Willem, just to name a few.
Moral of this post: Enjoy the time you have when your kids actually want to spend it with you. Before you know it you'll just be this embarrassingly uncool adult who gives them money.