Many hosting companies offer "Unlimited" hosting but is there really such a thing?

The quick answer is ...not really.

But many hosting companies are very confident they can provide you with more web space than you will probably need so they don't have a problem removing caps on resources.

As with anything do your research. Look into a companies history and search for reviews about them.
You have many to choose from. Take your time and pick the hosting company that you feel will suit all of the needs you will require to host your website(s).