For PhD graduates who are more interested in research and little teaching, which is better, a postdoc with a focus on research, or a (non-tenure-track) teaching position (lecturer, instructor, etc.)? I assume that both positions would be helpful when moving to a research position. The point with a postdoc is that even at top schools, the pay is low and they don't guarantee a good job afterward, while a teaching position, with 3-4 courses would be distraction from doing research.
In my discipline, mathematics, there is a huge range of tenure track positions, from very strongly research oriented positions to positions that are entirely oriented towards teaching. Most new PhD's would prefer to end up in a more research oriented position, but most tenure track faculty positions are not at that end of the spectrum. This means that a lot of new PhDs will ultimately have to settle for something less than the research oriented position that they have dreamed of.
If you're only willing to accept a research oriented tenure track position and would not accept a teaching oriented position then you should focus your efforts on getting a research oriented post-doc.
If you are most interested in a research oriented position but would at least be willing to consider taking a somewhat more teaching oriented position, then you should make an attempt to get some teaching experience by doing some teaching during your post-doc or by taking a position that is designed to mix research and teaching. For example, Dartmouth has named instructorships in mathematics with a teaching load of one course per quarter.
There are also non tenure track faculty positions (typically called "visiting assistant professor.") These are a good way to get teaching experience but it is extremely difficult to get any research accomplished while teaching a load of 3-4 courses per semester in such a position. These positions are sometimes created to temporarily fill the vacancy created by when a tenured faculty member leaves or retires. Sometimes the visiting assistant professor position turns into a tenure track position in that department, but you shouldn't count on this happening. .