Polls are always a bad thing.
1) People Vote for their favourite and members will vote for theirs so it goes down to popularity and automatically voids the idea and question being asked. The answer you will recieve will essentially be pointless.
2) People will vote instead of explaining why and then use poll numbers as an argument or as vindication for their empire.
What you should do is have no poll and instead ask the question so people have to explain why they think so. Not just say one or two words, but explain why they are using those terms.
Organisation, Activity, Skill, Range, Image, Wealth.
Communication/Organisation: How well the empire works as a whole as sometimes large empires can be an unwieldy collection of accounts rather then a efficent military unit. Even if active, having no structure means they can't make full use of their activity, nor enjoy the benefits of efficient teamwork.
Current Activity: How active an empire is, how active their players are on a whole. No point having infrastructure and large walls if the nightwatchmen are asleep.
Military prowess/Responce: How capable they are in using their account for military purposes to maintain their way or views. How successful they have been in campaigns, if they are able to bring adequate force to take on an enemy, how skillful or trained are the individuals in it or if they are relient entirely on overwhelming force.
Power Projection: How able are they to reach out to an enemy on all fronts. While massing and knowing how to use the account is fine, an enemy needs to feel like someone can get him, his friends and everything he holds dear. They need to feel that there is no escape and that people realise just what they risk losing or provoking when they touch a member of said empire. That is an empire needs to be able to reach someone on all servers, realms, areas and down any stat with nothing outside of their reach and that people need to realise that for it to act as a natural deterant.
Diplomacy and Politics: How capable is an empire in stargatewars outside of ingame mechanics. That is how well do they deal with situations, how well does their image play to their favour (Loved or feared are both beneficial), how the information game and forums allows them to advance, diffuse situations (through negotiations or force), extent of its alliance networks, contact networks, associates, ties, friendships.
Endurance & Attrition: How capable is an empire to survive in attrition. How wealthy it is, how long can it go on in difficult situations and simply outlast its opponents. How wealthy it is in resourcse to keep going ingame but more importantly how wealthy it is in spirit and moral and energy.
Most of these points are ignored and you'll normally get a "because they're the best/because they're strong etc" style answers if any answer at all. So these thread never give you a proper indepth look into the wider context of why an empire is the best. Which one is more capable at one thing or weaker at another as there is no single stat that determines which is the better.
Failing the above, you can always rename the question to which empire is the most popular and keep the poll
