There is no need to use a semi-colon: "Roses are red, violets are blue, I drink coffee, my wife drinks tea."

I think that ; is only really handy for delimiting lists: Firstly, I would like to thank the Queen <for>; Secondly, I would like to thank the President <for>; etc.

I think that the name is a bit of a pain: a colon is used for <statement>: <and here is why>. A semi colon is used for lists. However, the name seems to imply some sort of half interval and so people use them as an intermediary between , and .