Those all look interesting. The only briars I have experience with are Peterson pipes. I have the 312 model, which has the p-lip stem (helps keep moisture and tar out of the mouth). One suggestion is to make sure the walls of the bowl are fairly thick. A lot of heat can be generated, and you want the wood to be thick enough so it doesn't all transfer directly to your hand. Otherwise, the shape of bowl and stem is a matter of personal preference - usually dictated by how you hold the stem in your teeth and what angle the bowl ends up at. Your first link would probably work well for me, but everyone is different, and what is comfortable for one person might not work for others.
As for tobacco, I tend to go for the flavored Cavendish blends from McClelland. If you have been following the pipe threads, you will already know that most Virginia blends require significant age before they mellow out. Kyle and others sing the praises of Gawith tobaccos, and I would trust their judgment. I intend to pick up a tin of Gawith Rum or Black Cherry once I have burned more of my current inventory.