IBook died. Panthr. Can to save/transfr info to another Mac? with Tiger?

Question

Let's say a person for some reason didn't have a back up.
And then his iBook G4 stopped working and was advised not worth fixing cuz could buy a better, upgraded, but used Mac computer.
Can his info, all his docs and bookmarks and favorites, etc., everything, still be transfered from broke iBook to another Mac (a better mac, tho used.)?
Just take out the hard disc with all the info and somehow transfer that to a better mac?
And could he do that even tho his old Mac was Panther, and if a replacement mac had Tiger or Leopard on it? Would that work? Or would he have to remove Tiger or Leopard from the newer Mac and replace it with Panther to accept transfer of his older contents. And then assume he would have to go through normal upgrade procedures from Panther.
Oh, he's so confused.
But so thankful for your help.

Answer 1

Some of the answers depends upon the "better mac". The other big question is why did the other computer die? Was it the drive that failed, in which case there is no point?
To keep it simple, in all likelihood you couldn't just swap the drives and expect it to boot another computer unless the new one happened to be identical to the first. What would be easy would be to put that drive into an external enclosure, or get one of those adapter things that don't need an enclosure, and copy off all your files, or just turn it into an external drive for backup, etc. Since this drive is coming from a laptop I don't think it will fit in a desktop without an adapter, and laptops don't have room for two drives (I don't think, never having owned one myself). You can have two drives attached to a computer, or even in a computer. The format of your old drive is compatible with Tiger and Leopard for the purposes of reading files, but as I said before I wouldn't try to boot from it, especially not if the new computer is a new Intel machine.
If it were me, I would get an external firewire enclosure, and put the drive in it. I would then attach it to my new computer and copy off my data files. I would then wipe the old drive and use it for backup or data storage. Some of this will also depend upon the size of the old drive. If it is a 20GB drive it is hardly worth the trouble of continuing to use it and the expense of an enclosure and I would just find (maybe borrow) a suitable enclosure for long enough to copy off data files.