Our best players, your best players. At least three-fourths of the cost of a typical implementation is attributed to development labor. A hefty portion of the labor bill often goes to consultants. The entire team must be absolutely driven to meet aggressive milestones. Scope the project so that it doesn't grind to a halt under its own weight.
Many organizations make the mistake sometimes of drawing the scope of the project too broadly.
Starting with too broad a scope has two potentially disastrous consequences. First, the project team can become too large and unwieldy. A speedy implementation requires an agile, well-coordinated project team. If it's difficult to call the entire project team into a room for a meeting on short notice, it's probably too large. Second, the implementation timeline can become extended beyond a reasonable planning horizon.