Considering your needs and my experience, I'd recommend the Light & Motion Vega. Price lists at USD $199, but it can be found in the $150 range. I bought one this summer and have been commuting with it all this fall on city streets, and long stretches of very dark bike paths. I've been very impressed by it performance. It's very bright. compact, simple. No extra wires, a smart charger, and easy to remove and throw it in your pocket or bag.

I've found that it lasts me about a week between charges (3 hours run time, my ride home mostly) I use the flashing feature on well lit city streets, and the full power on the paths. I can't say enough about it. It has exceeded my expectations, and I love the simplicity of it.

good luck!