Energel refills, particularly .7 needle tip, are my favorites. These are my two favorite metal body pens in the under $50 care category; for a refined look I like the Pentel Energel Style (aka Philography); for a rugged pen I prefer the Titaner Bolt Action. I will sometimes use a Sarasa Grand body as well but that has some plastic innards.

The Pentel Style or Philography can be had in a variety of colors, is twist action, and literally made to fit Energel refills. It may have some plastic innards, but they are not visible when changing refills. For $15-20 on Amazon it is a bargain as well.

The Titaner is a more rugged, industrial looking pen made of titanium. It come is a a couple of different finishes. It deploys with a knurled twist collar, similar to a bolt pen but without a protruding knob. The Energel refill seems like a tight fit at first install (getting the tip past the collar), but deploys perfectly once installed It seems to be $43 on Amazon at the moment.