Leisure Las Vegas Style

I am calculating in grams/dl myself (Netherlands) so I tried to find a calculator that does this (for me strange) calculation to apply at my site (more than 900 recipes to convert: http://www.jannekes.eu ).
BUT:
A cup of sugar is heavier than a cup of flour.

Over here:

http://www.gourmetsleuth.com/cookingconversions.asp

it seems that 1 cup of flour = 4.41 oz = 125 grams,
and 1 cup of sugar = 7.05 oz = 200 grams.

So what I would like to have is a table (internet or yours) where the most common ingredients (flour, sugar, butter, milk .... ) already are "precooked" from cup in grams/oz/fl oz.

- And I really want to know if it's still common in the UK to calculate in oz (or can I skip the easy adding?)
- And if all the measurement in the USA is in cups (chocolate seems hard to do)
- And what the Australians are using.

Would you add, when you answer, what country you're from?

Very gratefull in advance!