My first aid kit would be a little different, as I don't have the same meds over here:
Esha 2000 (against fungus and bacterial infections)
Esha Exit (against parasites as ich)
Esha Hexamita (the same as Esha 2000, plus against hexamita)
Flubenol (which you can't buy anymore

)
PraziPro (agaist IP, gill flukes and a few other things - you can't get this one in Norway either, but I had it sent from the US)
JBL Furanol (contains nifurpirinol. Only for a real crisis. Takes some nasty bacteria - but this one will kill the filter bacteria)
Water tests! and a hydrometer
Extra cycled filter (we don't have biospira around here)
Extra heater
Should have had a QT tank, but I don't (always end up filling them with new fishes instead)
And the strange one: lots of emtpy ice cream boxes. They are very useful!
Declorinator (we don't have clorine in the water here, but you can risk them putting it in the water is extreme cases).
The possibility to airate water if needed.
Aquatic silicone
My own experience, but more important: the experience of thousands of people around the world, through fish keepers forums.
I think that should cover the most of it
