Lots of things to consider. I would use the tallest pot you own as a rough rule of thumb, so that all of your pots fit under the tap. Also, follow your manufacturer's instructions. And, if your pot filler swings, you also have to consider the swing distance in relation to any nearby cabinets.

So...I wanted to post the final results of the pot filler debate. We ended up changing our mind on the tile inset once we got the cabinets and lighting finished. The lovely grey glass tile took on a very dark and dingy look in the night time lighting. I was also worried that the tile grout would be hard to keep clean since it is behind the cooktop. So we decided to fabricate a piece of the marble from our counters. The piece was extra from the two slabs we purchased so the only cost was the fabrication and installation. So happy with the results. The potfiller was set slightly to the left and it is great.