Single pilot I prefer right seat, it's easier to deal with the radios & such since you don't have to switch hands on the cyclic. You also don't have to climb over the collective when getting in
There are several types that normally have left seat PIC (and a bunch that can be flown from either) - Bell 47's, S300C's, MD369 series. Some cases so they can squeeze in another seat up front, others just because they felt like it. Then there's the Hiller 12 series, with the pilot's seat in the middle...