Sounds to me like you need an alignment and some driving school or are riding on some bald ass tyres! I loved the set of ES100's I had when they first came out. Not bad on the tread life you got out of them btw!
Oh yeah, Edge Racing has some great deals. They have the tire I'm using for daily use for $50 each for 15" - Falken Ziex 512. Nice tire, good all around performance tire with long tread wear.