While most editions of D&D has included the option of playing a wide range of races, 4E is unusual in that they bring so many races into the core rules. I also think there are some surprises in the list of included races and those left out. I am for instance surprised that Orcs are still missing from the list. Hobgoblins could have been another option. Centaurs is another race I would have liked to see included personally, although their inaptitude towards dungeon crawls and general power level may be reason for them not appearing. Other races were saved for the various setting books.
Would you allow all of these races in your campaign (existing or hypothetical)? Are there any races you think are missing from the list?
Edit: Half-Orcs moved to PHB2, thanks Rabindranath