I would actually recommend either Galahad at Blandings or A Pelican at Blandings to a new reader. These are among the later Blandings stories, and the characters are much better defined by that time. For instance Lord Emsworth the pig crazy baronet is much more fun than the muddle headed gardener of the earlier Blandings books. Overall PGW was like good wine, got better with age, and I prefer his later books to his earlier ones.
That's true. He got better with age!
Always been a fan of the Blandings Castle short story collection, it's a nice place to start and has one of the best Blandings stories - Lord Emsworth and The Girl Friend.