My knees are getting worse as well and I have to say that the most comfortable and still good-for-all binding for me are the Forum Shaka. They have simmer canting, Gel pads, great straps and are very customizable. The only downside in my opinion is that they are rather medium weight, not exactly the lightest.
I've just read today that some magazine voted them the most comfortable bindings overall. But don't believe magazines when it comes to gear, the "awards" are usually bought by ads.
If you don't necessarily need canting I'd got with the Flux TT30. Great allround binding as well.