We have a plastic cubby/ climbing house with slide, swing set, trampoline, sandpit with a roof, blow up pool, big tonka truck, bikes, trikes, noisy push lawnmower, loads of balls, bats, todem tennis, easel, box of random plastic toys, chunky chalk, table and chairs, and a baby swing.

As far as I am concerned the outdoor play equipment has been the best purchases we have made. They sometimes cost a bit, but they have been used and used and will be for years yet. They are outside all the time, which makes bed time easier, and just general kid noise easier to deal with.
Your DS won't really want all that stuff yet though so I would suggest getting all the balls and noisy push around stuff now and putting your requests in to family about bigger outdoor items to add over the next couple of birthdays and xmases.