For the Powerlifter:
Here are some equipment choices, I suggest to get your own home gym started:
Here is a link to some Dumbbells of different weights. This way you can buy just what you need and add to your set later.
This is a nice bench in that it adjust to the different angles to hit the muscles from different positions. The foot pegs are useful for your decline crunches.
This door mount pull up bar is nice and it shouldn't mar your door jam since it has the padded handles.
This ab wheel is simple in design but can really impact the abs. It will strengthen you upper body as well.
Exercise Balls are great for squats with the ball behind your back, crunches and even doing your dumbbell chest work. When doing your presses with the ball under your shoulders you hit your core to keep your balance.