Ah yes, what a question this is.
A good rogue adjusts to the situation as needed. A good rogue pours on the dps when its called for, yet knows how to walk the agro line to the tee. A good rogue knew his zones inside and out. Knew every square inch of the dungeons he was in,and scouted each of them beforehand.
A good rogue can cr a corpse from damn near anywhere without getting wacked, and IF he was seen, have the needed means of getting out without dying to try again, (how many insta gate potions ya got?).
A good rogue is prepared ahead of time and can assume more than just the role of dps from the backside. He has achieved that 6th sense you only get from experience. Ever had to slow or snare a mob because the chanter or snarer just died on the inc.?
A good rogue anticipates moves ahead of time and adjusts his game accordingly. He knows when to bail out and escape so he can cr and save a raid countless hours, (how many of us have saved the night in VT >.<).
A good rogue knows when to crack a joke and lighten up the mood when things look bad. Giving some comic relief when needed seems to be our forte. Besides, who else would point and laugh at the rangers when they die? Thanks Wix for teaching me that =P
A good rogue knows his poisons inside and out. He knows how to utilize them to the utmost effectiveness. How many of us have trudged to that "pond" to get the barbs? I used to have all rogue nights where a bunch of us would go fishin' there and @#%$ the night away while we were stocking up.
A good rogue is an opportunist. They take advantage of situations and turn it into their favor. A good rogue can always find a way to make a profit and if any rogue says he is a broke rogue, he isnt a good rogue or he is lying. In which case he is even a better rogue >.< At least you real roleplayin' ones )
What makes a good rogue is not the gear but the choices he makes while playing. With that being said, a special shout out to the best rogue I ever knew, hey Wix..moo.