I use several, and that has changed over the years, and changes even now depending
For out in the sticks, or "up that tower" (RF feedlines) you really cannot beat the "big" Weller Butane. But they are WAY too "much" for small wire
http://www.weller-toolsus.com/soldering/irons/butane/weller-wpa2-weller-pyropen-kit.html
The big weller butane is big. It's huge. In fact, it's quite large. They can be had with several sizes of tips, I think the largest is on the order of 5/6 wide chisel. We used them to solder HUGE RF heliax center connectors
Next, go to garage, thrift, "used" stores and find yourself a real by-Gawud soldering IRON. Something from the 50's. The trick here is they are usually only 80-100 watts, which is not much in a "gun" but the "big tip" is the "deal"
I've actually got several of these, and paid less than 5.00 apiece for them
Doesn't need to be "this big" but believe it or not I HAVE one "that big"
Someone above claims the big Weller gun is "not enough". I have no idea what you are doing, there, but you can EASILY solder a pair of 10ga wires with the "big" Weller gun. You MUST wiggle /loosen/ tighten the tip nuts the first time you "get it out" to make sure they are tight. This is an ongoing problem with ALL Weller guns, but once you learn that simple work around, you are good
The D550 seems to have changed over the years, I swear some of the older ones were higher wattage but they do show a D650
Amazon shows them for under 60 bucks
http://www.amazon.com/Weller-D650PK-Industrial-Soldering-Gun/dp/B000TDGI18
But for smaller stuff, no 18--16 wires, a bench "pencil" iron around 60W is fine. THE SECRET HERE is get a large enough tip. GET A LARGE ENOUGH TIP!!! GET A............. get it? And with stuff like the Wellers make CERTAIN you get the RIGHT "correct" tip for the iron!!! Some of those are "trick" magnetic controlled tips, and you have to have the right tip for the iron.