I've got a fixed layout page and the client has asked for it to have "shades of blue". What colour would you recommend for the background, page wrapper background, text, dropdown menu and the buttons on the side?
Blue is a really diverse color. I suppose they all are, but 'blue' can mean anything from cyan all the way to indigo. There's a lot in between.
Ideally, it's good to pick colors for a reason; @Bakabaka's link in his comment gives some insight into color theory and the psychology of color. If your client has a logo or brand, it'd be really smart to pick blues that complement the brand's color scheme.
But if it's just a matter of picking nice shades of blue, then I find it's nice to use a site like COLOURlovers - you'll see that this link searches for palettes that contain different kinds of blue. Adobe's Kuler gets you some nice palettes as well.