1000 TB (Score 4, Interesting)

You just need to buy lot of 454 sequencing devices (http://www.454.com/) or Solexa http://www.solexa.com/wt/page/index and have big datacenter. Then you use those sequencers to re-sequence those 100 people and compare them with the reference human sequence. Big datacenter - You will need 30 Solexa devices and around 1000 TB data storage this is a nice task for Google datacenter.