Yup, sounds like this cat is bored, understimulated, lonely. Before getting a companion pick up a copy of 'Think Like a Cat': http://www.amazon.com/exec/obidos/AS...373726-6879000

It will tell you alot of ways to create a more stimulating environment, as well as how you choose a good matching companion for your cat and how to introduce a new cat to your resident cat. It's a great book and should be helpful for the life of your cat.

One more remote possibility is the cat has vision or hearing problems. Watch for other signs of this, and ask the vet to pay close attention to it when he is in for his yearly exam.