A Can of Man
Je suis aware
Ahh yeah those.
There really is no "good" way to do it.
As for a knife assailant, I have one word: chairs.
There really is no "good" way to do it.

As for a knife assailant, I have one word: chairs.
I'm with Bulldogg here as well. Learn boxing. A good punch is the fundamental base of a good fighter. Focus on that alone and only that and you'll have a mean ass punch (and the moves to go with it). Regretfully I've never been able to learn boxing properly, it's one thing I really really wished I had the chance to do.
Next, I'd say learn something that grapples. Judo over Aikido if you ask me. A lot of fights end up going to the ground and even in the MMA circuit, the grapplers are the ones who win the most tournaments.
No, don't move on to Aikido.
Anyways let me summerize what it is I said:
1) Boxing for at least 2 years.
2) Ideally Brazilian Jujitsu and Krav Maga.
3) If not possible, Judo and Muay Thai.
You might want to learn bits of other martial arts along the way but that's up to you.
Alrighty, boxing it is then.