Confused Which External Hard Drive?

I'm a new to mac, I just brought a new imac with a Time Capsule and looking at adding a WD external drive. Looking at two version of WD hard drives:

http://www.amazon.co.uk/gp/product/B00APSQCVS/ref=s9_simh_gw_p147_d0_i1?pf_rd_m= A3P5ROKL5A1OLE&pf_rd_s=center-2&pf_rd_r=03GD3F14497RVQJBYWTS&pf_rd_t=101&pf_rd_p =358549767&pf_rd_i=468294

or

http://www.amazon.co.uk/Book-Essential-External-Desktop-Drive/dp/B0047VOGOO/ref= sr_1_11?s=computers&ie=UTF8&qid=1363605535&sr=1-11

I'm confused...

I know you can reformat the 2nd drive for mac use but will it work with my Time Capsule? or Will the WD Mac edition be the better option? if so what are the advanagtes for have the WD Mac edition over the non WD Mac Hard drive?