No, it's not a complete list of all timezones. There are nearly 500 (no that's not a typo) timezones to contend with. I've reduced it to a list of about 70 (75 IIRC) which are comparable to the ones Windows uses. Incidentally I think you'll find XenForo uses a similar if not the same list.
Isn't this a complete list of all timezones?
Also, is the fact that I was by default on UTC/Dublin due to me probably not going to that area before, and thus having no default timezone...? Because I saved my time format, and didn't notice the timezone at that moment, and I immediately got an incorrect forum time (well, YOUR correct forum time if you prefer :P). I had to go back to the page and noticed that it was Dublin by default.
The timezone code has a bug where it can display the wrong entry in the list if the underlying timezone identifier has a _ in it. This is not a new bug and was discussed and investigated last week, I just haven't fixed it yet. But it still saves the correct timezone.
Check the timezone column in wedge_members to see what it's actually using for you - I'm on UTC Dublin, despite the server not being so.
Also, as far as I can determine, Amsterdam is not the same physical timezone but shares all the same rules with the Central European timezones, so that it is to all intents and purposes the same.
Regarding dates, I don't have a better solution, I'd prefer it to be as 'right' as possible, ultimately. April 1st would be better than April 1 which would be better than 1 April, but it's almost more a preference than anything else right now.
And yeah, optimising timeformat is one of those cases that it'd be neat but ultimately not a huge win in the scheme of things (IIRC, I already did some work to make it faster than SMF's by changing the setlocale call handling)