I reached the one blade forever scenario a couple of years ago with the Polsilvers and now i have a stash of about 7,000. This should last until I'm about 130 years old!!
I think I would have to choose the NOS Iridium Super shown in the picture below. Unfortunately I only have about 100-150 of those, and although I could probably extend the life of each blade to a month or two I would probably/hopefully run out. Also given the fact that these blade only works for me in one particular razor, I probably should choose a more versatile blade. The GSB comes to mind. It is readily available, doesn't cost too much and is a superb shaver.
Astra S. P. for me. I have a fairly big stash of these. They're superb and less expensive than many others.
I like Astras, Silver Blues and Polsilvers, But that said I'm finding more and more blade I enjoy using; such as Nacets, Sharks and 7 O'clocks.
I am down to only this one these days. I occasionally use a couple others, like the Gillette Swedes, but Astra is my main blade.
Feather Hi-Stainless works best for me in most every DE. Second choice would be Personna Med Preps or Lab Blues. I seem to recall enjoying many others that would be fine; Voskhod, Gillette 7 O'clock Yellow (but not the Blacks), Astras & Polsilvers. Been a while, but I got decent service from Generic Israeli Personna Reds.
Gillette Silver Blues for me. If they stopped production I would go with ZaZa Sent from my iPhone using Tapatalk
For DE Razors:- Gillette Nacet For SE Razors:- Schick Proline P-30 For GEM Razors:- GEM Personna SS PTFE Coated Sometimes is hard to stick with these blades depending on my mood of shaving.