Im not much of an XML fan either, but in many cases the extra overhead is worth what you get out of it. Using the DOM requires you to read the entire file (an awesomely slow process with large files, I watched a demo where the memory usage ticked upward...and upward...forever), but SAX and maybe the .Net reader are designed to be lighter. CSV's are ok, but it's not very rich. My favorite data transfer format is MS Access!
Andy