I have bought a few HP Business class SFF desktops now ... they are extremely well built and reliable (like DELL servers), and have a proprietary air cooling channel that draws heat from the internals and channels it out one side of the case ...
Cooler components are quicker components ... and Dual Channel Memory rocks too!
All I really do to them, is add a bit more RAM, and swap out the floppy drive for a 35-in-1 card reader.
All of my work rigs are now HP business class desktops, except for one IBM that has a pair of Matrox G450 cards in it for a dedicated video rendering box.