Fella lab colleagues,
Recently I had the dilemma of replacing my trusty, very old WLC100 that I had been using for all my projects since my college freshman years (circa 1993). I of course approached my lab guru, Mike Galusha for advice. My problem was that I needed both a soldering iron for large speaker projects, like soldering inductors or speaker wire to heavy binding posts and an iron for my smaller amp/preamp/dac building projects. The answer was you need two different types of irons and without much further verbage, Mike Galusha summarized it below nicely. In the end, I purchased both a Hakko 936 which is an incredible and a huge step up from the Weller WLC100 and the Weller D550 soldering gun which soldered wire to beefy posts such as Cardas in about 15 seconds! You need a very large surface area to heat up and the D550 takes the cake. Invest in quality equipment folks:
Anand,
It sounds like this is a pretty heavy gauge wire. I usually suggest the Hakko 936, reasonable cost, will likely last for many years, large selection of tips available. HMC is one place that carries them: http://www.hmcelectronics.com/cgi-bin/scripts/product/0460-0004/Hakko-936ESD
There is a look alike called the AOYUE 936 but has lower wattage and I have no idea about the quality. I know the Hakko is nearly bullet proof.
Personally when I have to solder heavy leads I break out the big gun, literally. I have a Weller D550 that is probably 40 years old, perhaps older. I've had it since I was a teenager and it was old then. I'll be 50 in a few months... Hard to kill one of those, just a big transformer and a switch, nothing to go wrong. 
http://www.amazon.com/Weller-D550-Dual-Professional-Soldering/dp/B00002N5LO
Or an American Beauty would likely be very nice as well. 75 watt model: http://www.hmcelectronics.com/cgi-bin/scripts/product/0400-0056/American-Beauty-3125-75W
IMO trying to get one iron that will do everything well isn't easy or cost effective. I also have an Edsyn Loner 951SX. It's rated at 95W but even with a big 3/16" tip it doesn't have the mass needed to overcome a binding post or some 10ga wire. I just pull out the old Weller and it's job done, nothing I do can resist it. 
There are not as many tips for the Edsyn and they are not as common but I've had mine for about 10 years and have used it nearly exclusively for that time and I've built a lot of stuff with it. Not sure which is better, this or the Hakko but I like having two... one with a small tip and one with a larger tip. Especially when working on tube gear. I use the large tip for tube sockets and terminal strips and the smaller tip for PCB's and anything smaller. Very nice not to have to change tips repeatedly, which I have had to do many times in the past.
Hope this helps. If I had to buy just one, probably the Hakko as everyone carries tips for them and they are less expensive. If you have the budget, get a big ass Weller for the heavy stuff. It will likely be passed down to your kids and the first time you don't have to spend 5 minutes trying to solder a Cardas binding post you will thank me. 
mike
Oh...and I enquired about the American Beauty but it was on backorder. Getting the Weller D550 solved that problem easily. It's made locally here in Raleigh by Cooper Hand Tools. The Hakko I ordered from HMC electronics, excellent service and personnel
Thanks Mike and thanks Lab,
Anand.
