Hard drive space

[Gamekid]

Since using my playstation 3, my hard drive has quite an amount of data stored on it. I have the 60 gig and out of 55 GB available, I still have 24 GB free which is quite an amount of space. Still the thought of running low on disc space is a thought that is in the back of my mind. With 24 GB free, you can run low on disk space. Many ps3 games such as bioshock and NBA I'm not into. I'm in the habbit of what I call archiving games, which means that when I'm done with certain games, I store them for future use in case I want to come back to them. If I do decide to upgrade my hard drive, I have some questions,

1) What is the maximum size that the ps3 can support? Is it 500 GB?
2) Trophies are saved on Sony's server, so you don't have to worry about any of that?
3) For ps2 game saves, it would be recommended to save the actual file to an external hard drive since the ps3 backup utility doesn't include ps2 game saves. How do you copy a ps2 game save file back where it should be. You create a ps2 memory card and then what?
4) For playstation home, everything is stored again on Sony's servers so other then redownloading all areas of home, your avaitor is still there if you log into home

With 24 GB still free, it's more of a 50/50 chance that I would upgrade my hard drive. There's only a handful of playstation 3 games that I'm watching, two of which are coming out this year, the others are still TBA.