What is the one item you bought for your LO that you regret purchasing?

I'm really trying not to buy too much before the LO arrives but I also wonder if I wait, will I not be maximizing an item's usefulness? Example: Amazon's price on the Baby Bjorn bouncer thing seems pretty reasonable right now, but I'm not sure if I should go ahead and buy it or wait until the LO actually arrives. Any experienced moms willing to share their thoughts on this strategy in general?