[CentOS] RAID storage - SATA, SCSI, or Fibre Channel?

I have a Dell PowerEdge 2950 and am looking to add more storage.   I know a lot 
of factors can go into the type of answer given, but for present and future 
technology planning, should I look for a rack of SATA, SCSI, or fibre channel 
drives?    Maybe I'm dating myself with fibre channel, and possibly SCSI?

I may be looking to add a few TB now, and possibly more later.

What are people using these days?   What throughput and reliability are you 
seeing?   What accounts for the cost differences?

Thanks.

Scott