Upgrade your hard-drive. Trust me, it's easier than you'd think. Here's a walkthrough of how to do it:
http://us.playstation.com/support/answer/index.htm?a_id=362
I upgraded from 40 to 500GB and couldn't be happier. Even at worst, you could just buy a cheaper 'bigger' hard drive (i.e. 160, 320) and then wait for the new announcement if you want to buy a slim PS3. Best of both worlds - gets you sorted for the mean-time, gets you a new PS in the long run.
But seriously, even I thought I would mess up putting in a new hard drive, but it was really simple. Just be careful with the screws.
edit: And if your current PS3 dies with your new hard drive in, simple buy the smallest hard-drive PS3 you can and move the hard-drive across. You'd have to reformat it and you'd lose all your installs, but you'd still keep a bigger hard drive.
edit 2: If you're worried about YLOD, make sure your regularly back up your saves either on a flash drive or cloud saves (if you have PS+)
