Roses are Blue...
There's a very "purpley" rose called 'Rhapsody in Blue' that's been available in the UK for a few years and is being tested by AARS in the US right now, and as gorgeous as it is, I think the average layman would still call it purple. That won't prevent me from including it in my garden though -- I love the color. I've read it will be available for retail sale in the US by 2006. I can't wait!
I do have another "blue" rose that grows next to 'Blue Girl', called 'Lagerfeld', (both are Hybrid Teas), and it is even less "blue" than 'Blue Girl', but since blue is not a color natural to roses, beggars can't be choosers.
There has been some recent, ground-breaking research in the area of blue roses, and we could see them in florist shops as early as next Valentine's Day. (Wouldn't that be an interesting message to send your loved one -- a bouquet of blue roses!) A biology/biochemistry/botany geek might appreciate a more scientific explanation here and here.
I, for one, cannot wait until such a true-blue rose is available to purchase as a shrub to be planted in my garden!