I know I have twice the HDD space as you but have you thought about downloaded only one or so PS+ titles at a time? As long as you "purchase" them they will be in your download list for later downloading, even if they aren't free anymore. Though 80gb isn't much now, I have 160gb and am doing just that while still having a ton of games on my HDD. You can also make room by deleting game data, not save data. Game data is all the installs and isn't worth keeping on old games since if you ever get those games again they will just reinstall and update the game data. The new HDD option is pretty good too though.
The YLOD issue could be a concern but I'm not sure if fixed models are more likely to get it again. You would lose BC most likely since the new rumored model probably won't have it. You can always remove activation on a computer if you forget.
Before the PS3 everyone was nice to me :(
