What would I like? Well, being the kind of person I am, I'd make a couple of stops....
(Don't know exact years, but I'll try anyway...)
1. First stop would be a year where I could purchase about three actual civilian production Walker Colts.
2. Next stop would be around 1909, and I would pay a visit to Herr Georg Luger. I would buy a few nice, minty Luger pistols and carbines.
3. Then, it's back to the US, in the 20's. I'd purchase some nice blued Colt-manufactured Thompsons, with a stack of L and C drums.
4. While I'm at it, some Single Action Army revolvers would be a good investment.
But if I could, I probably would go back to the year 1855, and stake a VERY large piece of property around Virginia City, Nevada. I'd take along some people with a background in mining and engineering as well.