Lets say I am given a Fireworks .png or a .psd, the first thing I do is open it, flatten the image and open it alongside my browser for easy viewing.

Then I look carefully for each "asset" I require, normally images unique to the page, things I can't easily create with CSS, etc.

After this I grab my lovely grid and start to plan out where each element will fit, crafting the HTML as I go along. I could use some kind of generator but it will never be as good as hand made HTML, it is always clunky and overly complicated.