The Choice: Buy a Liveaboard or Rent Cheaply

[snort]

And cheap is a relative term here on the California coast.
I will never be able to afford to buy a house near where I work (OK, I suppose I could, but I'd rather not live in gangland), so I'm wondering what the downside could be with living aboard a roomy boat for under 50K. Marina fees are about $300 a month and I figure up to 2K in annual maintenance.
I'm into sailboats, but there's a 35 foot powerboat that I could use as a home.
What do you suggest? Keep on renting cheaply (1K and up) or buy a boat?
To be honest, I probably would only take the boat out every once in a while to keep the diesels in shape.