Don't worry about an actual loadout of what you would carry. We're talking about a law that could possibly prevent you from ever obtaining more mags, forever.
Buy what you can afford, but I'd at a minimum have 10 magazines for any rifle or handgun. Magazines wear out eventually, though they can last a long time. I'd also have enough in case I had to really use them, lost some accidentally, or had to lend some out.
That being said, 10 at a minimum, but preferably double that for a rifle. If they are cheap, as some AR-15 magazines are, buy a bunch. Having 50 mags for a gun isn't alot. I have friends that own M1A's and only have 3 magazines, and two are junk aftermarket copies... and they think they are prepared.
During the last ban, I bought two HK USP handguns (I think when they first came out), one in 9mm and the other in 40 S&W. Being anal as I am, I had bought around 15 magazines for each gun, before I had even bought the handguns! I bought the guns, the mag ban came, and ended up not liking the guns. I sold them off, and sold the rest of the mags for $80 each at a gun show just walking around with a sign on my back.
I remember plastic Ram-Line 30rd, Ruger 10/22 mags selling for $75 each. Prices go up when you can't have it anymore. Get what you're comfortable with, even if you don't plan on selling any. Get mags for stuff that you don't own, but will in the future. If your favorite #1 rifle is the M1A/M14 and you only have one of them, but might get another M1A in the future, buy enough mags for two rifles. You can always sell them, and it's amazing what suddenly becomes "valuable" when supply and demand come into play. A rifle with no magazines or ammo is just a club.
