You know it's interesting that you're seeing lots of pain going the other way. I realized part of my issue with Silverlight was just how different it was from what I was used to. I don't like things I don't understand :) That being said, I did like the Stack Panel and the Dock Panel. I liked them because they worked more closely to the way HTML layout works. It was the Grid that I despised. The markup was tough to follow (putting Grid.Row="" and Grid.Column="" for each element inside the grid was stupid) and ultimately positioning in Silverlight was very much about absolute position and fixed dimensions.

As far as tips - vertical stack panels are just a series of unfloated divs (or other block element). Horizontal stack panels are a series of floated divs.

Vertical positioning with HTML/CSS can be tricky, especially in older browsers. line-height and padding/margin are you friends :)