Best Basic Theme to Customize

I’m planning to have a new WordPress site built, and it will be a custom theme. I’m wondering, however, what theme you would recommend I start from. I’m looking for a theme framework that is really clean and simple with a fast load time and is easy to customize.

I just read some previous posts online about this topic, but they’re all 2+ years old, and I’d like to know if anything has changed in the past couple of years. The top contenders for this a couple of years ago seem to be Hybrid, TwentyTen, Thematic, and Genesis.

What would you recommend of all the WordPress theme options available today?

Thanks so much for your input!!!