Esso XD-3 0W-30 (circa 2004, CI-4 standard) formula in one vehicle with a GM LH0 3.1L V6 engine. Haven't changed that for the past ~60k miles / 11 years, but its had the equivalent of an oil change or two in top-up oil mostly due to a minor valve cover leak. I originally selected this oil based on a BiTOG post by user "Olympic" who ran a fleet of railway crew transport vans and was easily achieving 50k mi service with UOA indicating that even longer could have been run. I've posted a few pictures of the internals of the engine over the past number of years, but the oil itself was not changed during such inspections or repairs.
Recently acquired a Honda K24A4 engine, and I just filled it with a mixture of Mobil Delvac Elite 222 0W-30 (the successor to XD-3, but reformulated to CJ-4 standards with lower TBN and lower ZDDP) and Mobil 1 AFE 0W-20. Roughly equal parts. The Honda's automatic transmission also received a drain and fill of Canadian full-synthetic Honda ATF-DW1. I also maintain a K24W that will receive the same next time it comes in. I decided that using the old-spec XD-3 wasn't a good idea because the high ZDDP levels might degrade oxygen sensors and catalytic converters prematurely.
Being in Canada, 0W is a must. And I have 3 5 gallon pails of the Delvac Elite 222 0W-30 HDEO that I got for less than $40 a piece (USD$), so there is absolutely no risk of using any other products.