You really should only use <br /> if you are declaring your files as xhtml. If you are declaring them as transitional or strict html 4.01 then you should use <br>.
I wouldn't recommend using xhtml, it is not really being taken up and strict 4.01 is the better (in my opinion). In xhtml, to make it valid (check here >
http://validator.w3.org/) you have to include every single attribute for all your tags, even if you are not using them and they have a null value. Which is annoying and makes it harder to read.
edit: the main reason css is better than tables is loading speed. To load a page with tables first the browser has to read the file to find the structure of the table, then read it again to load the contents.
With css it can all be done there and then. CSS also lends itself nicer to dynamic pages and easier reading for mobile handset browsers.
As with most people I jump around which projects I work on and which I drop for a while.
Currently I'm back working on Sioux, a Hollywood Western RTS.