Bare root irises tend to turn to mush, so plant them as soon as they
arrive. Here's a couple of standards irises:

'Autumn Circus'
http://www.vandycks.com/fall/z33210.31238.phtml
'Song of Norway'
http://plantsdatabase.com/showpicture/27981/

Japanese irises can get pretty big too.
http://easyweb.easynet.co.uk/~ianblack/japiris/

For something really out of the ordinary -- if you have the right
climate, try blue poppies:
http://www.christiealpines.co.uk/Pages/Meconopsis.html