When my son was 3 he really started loving books:
Kiss, Kiss, Yuck, Yuck is sweet, and is his favorite.
Puff the Magic Dragon---he loves those pictures!
The "Froggy" series
Chicka Chicka Boom Boom
Where the Wild Things Are
The Giving Tree
I have a beautiful Night Before Christmas book and also The Cajun Night Before Christmas.
We go to the library and just pick out random colorful books to try. He loved the 3 Little Pigs, Boy Who Cried Wolf, Jack & the Beanstalk, etc and we found some neat versions with lovely illustrations.
Now that he's 4 he also loves:
Roald Dahl's "Just So Stories" (he loves those, lol)
Several series books (Arthur, Martha Speaks, Berenstein Bears, Curious George, and Skip JonJones)
And I also read him "big boy books" that I know he's interested in the subject matter (Treasure Island, Kidnapped, Where the Pirates Are, Ralph Miller books, Black Beauty).
I do NOT like girly pink stuff (gag), but I read the Pinkalicious books to the 3 year old neighbor while babysitting, and those are quite cute, especially the one about purple.