The best things my wife and I bought for our son were:
1) His Stokke stroller. Excellent stuff. Where we bought it, it was a complete package as well. The only thing that wasn't included was the adapter set to click on a Maxi Cosi. (and even that was only 40 euro extra, so I can't really complain about the price of the extras)
2) Which brings me to his Maxi Cosi. I don't know how you can manage to be without one. It's his first car chair, yes, but handy for so much more as well!
3) Diaper genie, or, as they call it over here: Sangenic. You need it. Seriously!
4) The Bloom Fresco Childrens' seat. (or as we call it: 'the egg' ) Over here, those chairs Robotic is referring to are also popular, but this one is so much better. For one, you can start using it from day one until the kid is +/- four years old. Also, you won't bump your toes against it, which you will do with that other chair, trust me.

Bumbo is also cool, but our son only had about 1-2 months of joy out of that one. Between his fifth and seventh month. After that he had figured out how to crawl out of it.