I would suggest a high-heroic starting level. I've voted 7th since this gives an extra encounter power.
Thanks Steve - I was reflecting on it more this morning and I had already come up with 7th as having several advantages. In the Monster Manuals etc the tough 'mundane' humans, orcs etc tend to be in the 7th-10th range; starting at 7th allows the DM to use lots of the listed MM stats like 8th level orc chiefs, 9th level pirates, 7th level highwaymen (in MVTTT Nentir Vale) etc. As you say it's less complex than Paragon, but reaching Paragon is within reach and can mark a transitional point where the PCs begin to transcend those mundane threats.