SoundAdvantage - 7:27 pm on May 29, 2012 (gmt 0)
I use both :)
I find Illustrator's lay-out capabilities are much easier to use. I usually create the site in vector (laid out on a grid for reference in the final site) convert it to raster in Illustrator's Export for Web features and use Photoshop to edit individual elements if necessary. I will also use Photoshop to make a feature graphic or anything that needs complicated blends or textures.
Hope that helps.