Someone who cares about what the group achieves, rather than who gets the credit.

Ivy

Someone who is humble. When it is the chapter who has achieved an honour, they should recieve the recognition, not the president. Likewise, glory should be the least of their concerns. The well-being of the chapter and the brothers and sisters that comprise it should always come before personal gain.

Someone who is honest. If a leader is not trustworthy, he or she is useless. Why follow someone who will lie to you? Honesty is an important part of Greek ideals.

Someone who is realistic. Pie-in-the-sky ideals are wonderful, but they only matter when you have the knoweldge and wearwithall to back them up.

Someone who is honourable. A president is the representative of the entire chapter. They must behave accordingly at all times, no matter if they're in badge, letters or just jeans and a t-shirt. This means the president must be accountable for his or her actions, able to admit a mistake, willing to take the moral high ground even if it doesn't suit his or her interests, and above all strives to fulfill the goals and expectations of the organisation.

Someone who is political. A leader is well served to know how the wind is blowing and what would be the best move to keep the chapter sailing. Being able to navigate campus and Greek politics will keep life a little more stable for any chapter.

Someone who is charismatic. Being a good brother and sister is meaningless if you cannot communicate effectively, win friends and influence people. Leadership does often boil down to making decisions and making them stick. Being able to do it with honey instead of vinegar helps.

Leadership is tricky, and I'm almost relieved I've not been called upon by my chapter to serve in a leadership capacity. It takes real love and dedication.

In addition to the other stuff that's been mentioned, a leader shouldn't just sit around giving orders. If there's work to be done, the leader should be helping if at all possible, especially if it's difficult, dirty, or thankless. For example, my company added onto its office space last week and the new area had to be painted. We couldn't afford professional painters, so the employees had to paint it. The boss was with us the whole time, brush in hand. :)

In addition to most of the other comments mentioned, in this forum, a leader must have at least 3 minimum characterics: be strong (admit when wrong), and encourager (sp?), and lead by example.

I like SisterMadly's ideas. I'd like to add this, from our Creed:

"...the responsibility to do my best in whatever I undertake, always remembering that leadership requires confidence tempered with humility, and courage blended with tolerance...."

A good leader should not have too many committments outside the organization s/he leads, if so s/he needs to step down from the position.