Ask HN:External Harddrive or NAS for mac/win home

Hi, I want to backup data both from my macbook and windows desktop. Is it possible using a NAS like LaCie Network Space 2 to backup data from both the machines on the server. I 'm guessing I will have to partition the drive and then store the data separately on the respective drives. Can someone also share their experience with Lacie NAS?<p>Secondly would an external harddrive attached to wifi router be a good option as compared to using NAS?<p>Thanks J