For steam service, it depend on the pipe sizes, pressures and temperatures of your application. If you are talking about less than 100 psi steam and pipe sizes less than 2", then commercially available threaded globe valves (with stainless trim) are the most cost effective solution and will provide excellent throttling service. Using a high performance metal seated butterfly valve would cost big bucks and are really only good for 2-position service.
If you are talking about 2" to 6" pipes, then commercial flanged globe/cage valves are excellent for steam. DeZURIK makes a good pressure balanced globe/cage valve for steam up to 150 psid.
Ball valves would be OK for on/off but not modulating control, in smaller pipe sizes. The new "characterized" ball valves available in the commercial industry are not rated for steam.
For O2 applications, u might wish to consider the fluid medium:
i. O2-Gas: valves of ductile iron/SS with rubber (i.e. NBR) seating will suffice;
ii. O2-Liquid (-297DegF): 316SS disc with teflon seating will be good.
In general terms, Triple-offset metal seated butterfly valves, with the appropriate materials selection and devices, are suitable for all  of the three applications mentioned.

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