eGo 2.4ml CC CE4 Clearomizer.
I just talked about this in a post a few minutes ago. Not too big but holds enough juice for hours of vaping. I also love the less than $2 replacement coils that are very consistent and reliable. I generally toss the coils after a week of constant use, they start to degrade in about ten days or so with heavy vaping. Since they are so cheap, I do not worry with any sort of cleaning or whatever, and I just vape on.
I am gonna try the new T3's though. I have heard some good stuff.