I love, love, love, hand embroidery. In addition to the designers mentioned above, these are some of my favorites: Gail Pan, Lynette Anderson, Bareroots, Bird Brain, Blueberry Backroads, Red Button (something)... I like Sulky 12 weight cotton thread. It comes on a regular spool. It's equivalent to two strands of regular floss. Great colors too! I just bought a bunch of muslin to try instead of iron on interfacing.
Machine embroidery is a whole 'nother beast, in my humble opinion. Although I have noticed a new trend at the quilt shows, machine embroidery that looks just like hand embroidery. Kinda sneaky. Bird Brain Designs has started dping this with their patterns. Smart move for them to open up a whole new market but I like the calm feeling I get by doing it by hand.