Koss PortaPro, by a large margin.

There might be one exception but it’s historical and I have no idea what my impression would be today. Back in 1988 I tried Bang & Olufsen Form 1. I put them on my head and instinctively looked at the ground behind me because I thought they fell off my head. Those were 150g headphones and I didn’t feel them. But it was a long time ago and I’m not nearly as impressionable as I was then.

These are Koss’ de-facto flagship product. There is a reason they haven’t really changed them since 1984.

If you enjoy the PortaPro then the 99 Classics may sound more to your liking. I find them quite balanced.