A good knife.
Seriously. Not from Sears. Not from Ikea.
I have these:
and
Hand-made japanese steel.
If you're going to be doing a lot of cooking, be safe and get a nice knife. Sharp knives go where you tell them. There are no surprises with the knife slipping off your tomato and cutting your hand.
As for getting ingredients... instead of trying to pick and choose random things that you might need, I would look at your recipes and pick some things you want to make. Go out and get the ingredients. Then, you'll start accumulating spices and condiments as you go. As a bonus, they'll be things you like, rather than things that we like.
I always have tomatoes, eggs, butter, garlic, onions, bread, milk, cheese (cheddar, mozza and goat cheese... probably a nice blue cheese as well).
If you've got plenty of counter space, go out and buy 3 nice glass jars that can seal properly. Fill them with pasta and leave them on your counter. Its a decoration, and a better way to store it than a cardboard box.