Which decrease stitch should I use?

I need to decrease by one stitch several times, spaced fairly far apart, when I transition from one stitch pattern to another. Which is the best one to use that will be the least noticeable?

I always use a K2tog. They are easy and the least visible IMO.

Yep, when you do several decreases evenly spaced across a row, a k2tog is usually the default.