We were able to borrow an activity gym/playmat and an exersaucer from friends to save some $. I'd really recommend doing the same for these two toys because they are only used for 6 or 7 months tops.
Jump baby Jump! OMG the Jolly Jumper. S lived in this thing from months 4-8 until he physically grew too tall for it. I'd put him in, turn on Gangnam Style and let him go. It was amazing. Hands down his favourite toy as a baby. Even when he grew too tall to really jump, he taught himself how to just swing in it. Hilarious. Also, like the playmat and exersaucer above, we borrowed a walker from a friend. Not only does it save $, but in the end, it does lower the amount of baby 'stuff' you have to store.
Stay tuned for a whole other post on the best books for babies, but they are absolutely to be included in the "toys that get play with" section. S loved 'feely' books. Any kind of book that had textures in it was a hit at our house. And board books are a must. S is perpetually teething, and he will actually chew the corner right off a book if we're not paying attention, so his books need to be durable.
NB - most of my links are to Amazon, but they aren't always the best price. Be sure to look around :)
Know of any other 'must have' toys for babies? Add them to the comments section below!