I am getting ready to put a 220v outlet in my garage for a future plasma and at some point a larger welder. I was wondering what the "standard" or best type of outlet that I should go with? Whether I should do a 3 prong dryer type or the one below? There were a ton at home depot to choose from.

14-30
http://www.frentzandsons.com/Hardware%20References/plug%20imiges/14-30r.jpg

6-30
http://www.frentzandsons.com/Hardware%20References/plug%20imiges/6-30r.jpg

I went with the 14-30 pictured above. I believe the 6-50 is actually the common welder receptacle pin style. Are you planning on making an extension cord? I believe nice well insulated cords are available with molded plugs in the 6-50 style from welding suppliers. I haven't ever seen an extension cord with molded 14-30 style plugs, but I haven't looked hard either.

What "larger welder" are you planning to buy? The amp draw of that machine may limit your choices.

EDIT: One advantage to using the 6-50 receptacle is that you can run three conductor extension cable for it. With the 14-30 you need to run 4 conductor cable, even though your welder doesn't need four conductors.

I've never seen anything but a 6-50P on any basic, single phase 220V machine. So you want a 6-50R.

My "larger" ESAB plasma requires a 50A circuit, my Hobart 210 only needs 30A (actually IIRC it only pulls 23A max).

Just size your wire according to your breaker; you can still use a 6-50R but if you only run #10 then use a 30A breaker (duty cycles not taken into consideration here).

Just to double check, you said this one (below) is pretty common and I can use it on a 30 amp breaker with 10/2 wire? (sorry I am new to this).

http://www.frentzandsons.com/Hardware%20References/plug%20imiges/6-50r.jpg

My wifes father said to use a 6-30 but to be honest I have never seen a plug for one of those.

they'll all do the job, just depend on what your welder plug comes with. Mine came with the design above so thats what I used on all my stuff.

Just to double check, you said this one (below) is pretty common and I can use it on a 30 amp breaker with 10/2 wire? (sorry I am new to this).

http://www.frentzandsons.com/Hardware%20References/plug%20imiges/6-50r.jpg

My wifes father said to use a 6-30 but to be honest I have never seen a plug for one of those.

My thermal dynamics cutmaster 101 came with this type of plug. However my first welder (old wards stick welder) had a stove plug on it so I've continued to use them. For the TD 101 I just built an adapter/extension cord to convert it since it would have been $100+ to convert all my junk over.

Most welders i have seen come with a 6-50 or no plug at all. I have mine run on a 30 amp breaker and a short drop of 10-2 to the plug from the box. No problems so far