I've been running a Seagate Momentus XT 750gb hybrid in my laptop for the last two years. I've been very pleased with it. It boots nearly as quickly as an SSD, and in general use it feels like a fast desktop drive. I even bought a second one as a spare a few months ago.
That said, no one...
How about an external USB sound card? They're not terribly expensive, and several on the Egg are supported for Windows/Linux/MacOSX, if that's a consideration.
That cooler will definitely not fit if you include an optical drive in your build. In the GD04/GD05, the optical drive overhangs the CPU socket, so a low profile HSF is required. In mine, the stock Intel i3 heatsink fits, but anything much taller would not.