I use my P67 mostly for landscapes - I've developed a tolerance to lugging the heavy beast around with tripod etc...!
I use the (newer) 55mm and 75 mm lens, both v sharp. I also use the 135 macro, v sharp when used in macro mode, less good at anything else beyond f8; and the 300mm lens, which is v sharp, but very difficult to avoid shake with beyond f8 in my experience.I used to own the 45mm lens too which was v sharp, but traded it in as I found it just too wide for my style of photography.
My apug users gallery will show some pictures taken with these lenses.
I have the standard 105 mm and the 200mm. I have pictures made in a scrap yard and at 7000 feet of altitude in a hot air balloon made with the 105mm and both are tack sharp. Same with the 200mm.
Before my next purchase, which will be the macro lens, I will buy a good tripod. This beast need something strong against vibration and the one that I have (Manfrotto) is not doing it's job, besides beeing heavy.
My first professional camera was a Bronica S2A. The lens I used most was a 50 made by Zenzanon which was sharper than the corresponding lens made by Nikkor. Then the opportunity came along to pick up an entire Blad system for cheap, and of course I did and was very happy with it; customers recognized the camera immediately... and I billed them more!
In 1983, a friend offered to loan me a Pentax 6x7 body and any one of several lenses to try. The first experiments were with the 55, pitting it against the Blad 50 in three situations where I most often shot... they were equal at the small apertures but the Pentax was definitely sharper in the corners at wider apertures (will I be burned for heresy now?). I was doing more table top work and so tried the 135 Macro next- and at distances under 8 feet or so, it was amazing at f/11-22. I sold the Blad system for a handsome profit and bought into the Pentax 6x7 with money to spare and have lived happily ever after.
The only caveat: some of the old series lenses (thinking of the 200 especially) are not as good as the new series.
And the 120 soft focus is arguably the finest roll film format soft lens ever made.