Depends on the model of WD drive. Nevere use desktop/laptop drives (Green, Blue), and don't use NAS drives (Red). Only certain versions of the RE drives are provided by WD to work on Dell controllers. So, if it is not an RE drive that WD states will work on the PERC controllers, then use the Dell drives. Also, for future reference, don't order drives directly from Dell. Buy the same certified drives from suppliers. For example: [URL] [URL] 
Just ordered 2 new 300 GB hard drives from Dell at 300 dollars each.  Have Perc 5/i Raid 5 config.  I was told that I could get 2 WD hard drives much cheaper at Microcenter which would work as well?  Should I stick with the Dells which are in transit?  Thanks
New hard drive Dell PE 1900