I like the old-style Ungar Standard Line soldering irons. The heating elements have edison bases and screw into a socket on the handle. Most of the heating elements have interchangeable tips that screw in to or screw on to the end of the element. Some of the higher-powered elements, however, have built-in tips for greater heat conductivity to the tip. According to some of the folks on ARF, the elements with tips are good for soldering to steel chassis.
Weller bought Ungar a while back, and Weller was swallowed by Cooper, then Apex Industries. But they still list a few of the old Ungar standard line components in their catalog and price list.
I happened to come across a few 47 1/2 watt elements with silver-plated iron-clad copper tips at the last MIT flea. They were only a couple of bucks; well worth it in my opinion.
Here's a couple of scans of the Ungar Standard Line from the Allied and Lafayette 1965 catalogs.
Allied Radio catalog 240, 1965
Lafayette Radio Electronics catalog 650, 1965