If you have quite fair hair you can bleach it blond and the baldness won't show so much, although this only really works in the early stages.
You can also get a product called Dermatch that is basically makeup that covers your scalp, again, only works in the early stages of baldness.
Don't mess about with wigs or hair transplants, they're way too much trouble.
The only combovers I have seen that work are when you just make a 'bridge' between the narrowest part of the bald spot on the top of the scalp. As soon as you start trying to cover your whole head with long strands or having a parting below the normal height, don't bother.
Best thing once it's too gone to cover up, just trim it short to around 1/4 in and spike it up a bit on top. Don't shave it off completely because you'll look like a cancer victim.