I find the selection of books and patterns is always excellent at a quilt show. I always try to find new rulers (I'm a sucker for a new ruler or template!) or tools you don't already have. There are often the vendors with gobs of new thread that is always tempting. One thing I DON'T generally buy a a quilt show is fabric, because the lines for it are generally long, so I write the name and manufacturer down so I can locate it later.