So i loaded it up and it even remembered my last spawn point, right in my home. I looked around and everything seemed just fine. Then i walked downstairs into the basement.
Wait, what's that torch doing there? Wait, that's not a torch, that's a fire!
Luckily i actually had a couple of buckets of water available so i started running about dousing the flames. Eventually i just left the first patch of water flowing on the first floor and ran downstairs to get any patches that weren't already extinguished by the running stream with the second bucket of water.
Finally, it seemed like i had things under control. Most of the basement floors were underwater and the lava pool in the subbasement had been extinguished, but i couldn't see any more fire.
So i swam back up to the first floor, and then i looked up. The first three floors of my house were either already ash or engulfed in flames. Clearly somehow a spot of fire had gotten past me at some point while i was dealing with stuff downstairs. (Note however that the roof was not on fire. The roof was made out of glass.)
It's really too bad i wasn't recording at the time. All and all it was a pretty classic "Oh #$%^! my house is on fire!" Minecraft experience.
What i can't figure out is _how_ the fire started. I went back and recopied the converted save, and when i loaded it up the basement was on fire again. But then i reconverted the original save (which i'd thankfully kept a copy of) and _that_ time everything was fine, no fire at all.
I guess the conversion process hiccuped the first time and decided there ought to be more fire? I dunno.
(Also, where's that Sephiroth icon when i need him? =)