Stephen Graham - he was in 'This is England' and 'Snatch' (amongst other movies). He's a really great actor, I've seen him do completely different accents, have a completely different physique and just generally seem entirely versatile and believable. Little known actors or actresses often get forgotten about, even though his ability is probably greater than some hollywood stars. Same with Toby Kebbell and Paddy Considine, both British actors.
I would also say Michael Fassbender too, but since 'X-Men: First Class' a lot of people seem to like him, so maybe he's not so underrated anymore (still brilliant though!)
And Mark Wahlberg (another crush! Am I biased? Haha) although he's alwasy been a popular actor, he's never been talked about as a great actor. But 'The Departed' and 'The Fighter' and even 'Four Brothers' - he's a very good actor. I'm probably biased. Haha :)
BQ: I've got in on DVD. I think you'll enjoy it! It's a great, entertaining movie. I loved it when I was younger, don't love it quite as much anymore but still like it. It's a must-see to any movie lover.
BQ2: Probably The Little Mermaid! Disney version. But actually you mentioning a faun, Pan's Labyrinth would be a close second :)
BQ3: Natalie Portman and Keira Knightley. James Franco looks a little like James Dean.