No amount of advice will completely answer your question. The best way to to go to a shop and feel the weapons yourself, to see what fits.
But since you asked, the Sig Sauer P220 is a large frame gun, as is the Glock 21 and 20. You might also consider the ever popular 1911/1991 framed guns, and the H&K USP. All are available in the uber popular .45 ACP. (Glock 20 in 10mm)
All are easy to use, but take training to become minimally proficient. All are considered reliable, but all also have some occasional quirks. To find yours, you must (Zen moment ahead) become "one" with the gun and be comfortable that it will work when you need it to the most.
As for duty gear, I will always and forever recommend at least a Level II holster, and suggest a Level III. The Safariland Raptor series holster is what I currently use and recommend. I have also used their SSIII holster and it works well too.