As well as the size and the ability to be rolled up small, silks also have the advantage of being extremely colourful. The red or pink cape used in bullfights isn't there to excite the bull (which can't see colours). It's there for the crowd.
There is a book on the subject (possibly more than one) Rice's Encyclopedia of Silk Magic - four volumes of it in fact. It seems to be available on CD-ROM too.
http://www.hanklee.org/xcart/product.php?productid=7913
The Slydini Silks are great, although I never got round to mastering the bit where the spectator ties the handkerchiefs together!
While they need other props, so aren't really suitable for walk-around, I have fond memories of performing the 'Crystal Tube' effect, and also 'Silk Serenade'.
The Wonder Box (or Wonderbox) is a nice prop too. I saw it on TV in the very early 80s and was completely fooled. I had absolutely no idea where all the silks were coming from. I believe it's an original Davenports effect (well, that's what I read in an old magic book). There seem to be some absurdly cheap versions around.
Oddly enough, it doesn't seem to be featured on the Davenports website, although it's mentioned in Duane Laflin's double DVD set, 'Sensational Silk Magic' and 'Simply Beautiful Silk Magic', which they do stock.