Actually, safari use's the least memory. There is a comparision video which does the main browers based on performance, look/quality, Javascript, speed, HTML5 speed, Flash speed, memory usage etc. It's a tie between FireFox and Chrome(Chrome has the best HTML 5)
#edit
Firefox just released Firefox 9.0 yesterday, the website is loading correctly for me now.
#edit
Firefox just released Firefox 9.0 yesterday, the website is loading correctly for me now.