I love children's books.
I decided to start collecting children's books quite a while ago. Now that David & I are married, we decided together that spending money on children's books was a much better use of our income than buying new DVDs or other such things.
One of my favorite series is the Charlie and Lola series by Lauren Child. It has a very unique style of art and writing and is a lighthearted break from the traditional PBS-style of cartoons and books. I actually used to watch it on Playhouse Disney on my days off all the time. :)
We joined Book of the Month Club 2 to help out our collection. We created a "reading list" of books we wanted and each month, they ship us the next one on our list. Each book is only $10 with no shipping. It's quite awesome, actually. We even got Your Favorite Seuss, which is a fatty collection of Dr Seuss stories for only $10. (In the store, it was $25!) Can't beat that. And I'm always scouring those sale bins at Borders and Barnes & Noble for good deals. I got a couple of good books the other week for $7 total. I felt like quite the thrifty shopper.
(Oh... and just in case you get the urge to ask... we aren't collecting children's books because we are expecting. We are collecting children's books because we are expecting to have children eventually. That is all.)