I saw him in Trainspotting (a masterpiece, IMO), and another one of Danny Boyle's early gems called Shallow Grave. He was pretty great in both, and I was really anxious to see how he does in Star Wars. It was kinda disappointing that his role in TPM wasn't more prominent, but I think he really shined in other two.I for one wasn't all that sold on the idea of Ewan McGregor as young Obi-Wan. Before the cast of Episode I was announced I think I'd seen him in just one other film (Trainspotting) and wasn't very familiar with him, so naturally the idea of this new guy stepping into the role made legendary by Sir Alec Guinness wasn't the most exciting one.
Honestly, I'd be way more excited about a standalone Obi-Wan movie starting Ewan.