Rogue's at level 55 need ether the Goddess set or the Giant Fist set.
If you want to lean towards more critical damage over physical damage, i'd recommend the Giant Fist set.
If you want to lean towards more Physical Damage over Critical, i'd go for the Goddess set.
Both sets drop in HoS.
If you want a better set than both of them, go for atrocity set. Its harder to get and more expensive, but even some of the level 67 rogues still use it.
As for accessitories, i'd recommend the Flame Dragon Power set if you have the money for it, otherwise i'd go for the dilan'y set in HoS.
Heres the links for the gear.
http://www.runesdatabase.com/itemset/610181 Is the flame accessitory set.
http://www.runesdatabase.com/itemset/610165/will-of-dilan'y Is the Dilan'y Accessitory set.
http://www.runesdatabase.com/itemset/610…ist-battle-suit Is the Giant Fist Armor Set.
http://www.runesdatabase.com/itemset/610…-of-the-goddess Is the Goddess Set.
http://www.runesdatabase.com/itemset/610186/atrocity-suit Is the Atrocity Set. 
