skip hop kids' backpack - they've got a ton of animal choices (DD didn't use it until more like 18 months, but they're cute, $20, and she looooves to fill it up with stuff and carry it around.)
mega blocks
little tykes swing
it's $25 right now, but the bubble mower was a HUGE hit (if they've got space to store it and baby is walking)
My 3.5 year old still plays with his Battat trucks that he got at 11mo. They are awesome, we have the firetruck, cement mixer, garbage truck & end loader.
Board books - Little Blue Truck, Brown Bear Brown Bear What Do You See?, Goodnight Gorilla, Hippos Go Berserk, I Love You All The Time
My 15 month old loves: Mega blocks Play food for her kitchen Any type of ball The B. toys dog shaped guitar from Target Books...the pout pout fish and trains go are her two favorites. A shape sorter cube Crawling tunnel