I was in the same boat when I got certified, and I'd recommend renting for a while with an eye toward trying out different things and finding what you like.
When I started, the shop required that we buy our own hood, boots, and gloves, so I rented everything else. As I started diving, I realized that in New England water you need good exposure protection or diving won't be any fun. I found most rental wetsuits ill-fitting, and pre-peed-in, so I made the investment, was very happy with it, and had one thing less to rent the next time.
Then I bought mask, fins, and snorkle, so I could both be sure of a good fit, and be able to at least snorkle when I wanted to. All the while, I continued to use rental equipment, and tried to get at least one thing I needed every time I went.
A weight belt was an easy one, as was a knife. After a dozen dives, I bought my own regulator, and it wasn't long after that that I'd tucked away enough money for a BC. That was a big one... once I had something I liked, I could start making adjustments to trim, and found my diving improved dramatically as I got used to diving in the same gear every time.
Of course, as I became a more and more avid diver, I've upgraded or changed equipment a few times, so I'd advise you to consider how far your diving might take you, and see if you can get gear that'll be as appropriate then as it seems now.