Most of my guns are US made, and I generally like supporting US manufacturers of quality products. That said, I will buy a quality gun so long as it's not made by the Chinese, as I generally oppose the continued outsourcing of products to China.
My now-sold Browning M1919A4 beltfed was made in the US, exported to Israel, and modified with Israeli components to fire .308.
My XD pistol is made in Croatia. I've owned (and will buy again) Glock pistols made in Austria. I'm considering getting a CZ bolt action .22 rifle, which is obviously made in the Czech Republic. I might own an AI (British made) rifle in the future.
Otherwise, the Ruger, Remington, SA M1 Garand, Mossberg, and Busmaster rifles I own are all made in the US.
I buy US, Czech (S&B), and Russian (Wolf) ammo in great quantities. I buy what's cheap and what works, depending on the situation (I have begun buying more US made, brass cased ammo as I can reload them for cheaper than it costs to buy new non-reloadable stuff).