Of the current candidates, I'm thinking Owen might be best. People may have heard of him but he's not a household name yet like some of the others who have been mentioned in the same breath as the name Bond. Ioan Gruffud is even less of a name but I think the superhero turn in FF might hurt his credibility. But that mental decision remains to be made until after the film comes out. I'll reserve judgment until then.
Bale would be a good Bond, but I think too young. I still think that Bond should be right around late 30s at the youngest. 40s is better. That's just the image I have of Bond in my head.
Orlando Bloom? I'd never come within 100 feet of the theater if he's cast.