This is one of those topics that's been hashed and rehashed here. There are lots of different opinions -- some swear by using a good wash + water as a lube; others (me among them) prefer to use the QDs that come with clay. As a trial, I went to the search page, and entered "clay+ lube + soap" as the keywords, and turned up most of the threads that I've found most helpful in regard to your question. I'd suggest you try that search, and read thru the threads. They'll not only address your question about QD vs. soap-lube, but give you lots of detailed, practical tips about how to use the clay appropriately.
What clay will you use? The most popular here seem to be Mother's, ClayMagic, and the wildly wonderful Autopia Glide + Block combo available in the Autopia store.
