What kind of poll is this? For the average guy, a MiG is the best tool.
welds good with little skill, both steel and aluminum with the proper setup.
We had a welding class in high school, I used a plasma cutter, torch, mig, tig, and the 'sticks'.
I use welders on thin materials, because that is what everything is made out of thin materials.... which a mig can take gladly. I've welded up mower decks and things with stick welders, it sucks!

Stick and to a extent acy/ox tourch requires some skills, and for that they are "special use" items.
A Mig and a TiG are fun to use because you got much control over the processes, wire speed and voltage and heat. With the tourch...I watched my uncle weld up a exhaust on a car using a tourch and coat hangers!!!(what a PAIN that was)
The 'sticks' are okay on thick metals, but lord have mercy on thin metals!! I can't tell how many times I've burned thru a part, and then close the hole.

That takes skill, somthing that is hard to keep unless your welding all the time, too much frustration with stick. Especially when your all sweaty and get jiggled by the electrons.
[edit] what about spot and heliarc welders?