Hello everyone! I bought a netbook (acer aspire one d255e atom n455e) wondering if i should go with xp or 7?

Windows xp pro sp3 or Windows 7 ultimate? I wonder if my netbook can take the load of windows 7 ultimate. I don't want to enclose my netbook with the limitations of windows 7 starter and afraid that the ultimate edition would only slow down my netbook's performance so I was thinking about windows xp pro sp3 which I think is lighter but too outdated. So what do you think? Thanks in advance.