In a survival scenario, it will be practical to own an AR-15 type rifle in .223/5.56. If anything breaks on your AR-15, you will be able to find spare parts for it. I know that AR-15 rifles with 16 inch barrels are very popular. I prefer the AR-15 with a 20 inch barrel - the longer barrel makes a somewhat better long-range use of the small bullet than a shorter barrel.
Likewise, parts are widely available for 1911-style pistols. A basic 1911 is a good choice. Of course, many "foreign" handguns are made in the U.S., such as Beretta, SIG, Glock, etc. I like the SIG pistols - I own several and they are accurate and super-reliable. If you are interested in a 1911 style pistol for home defense, you do not need a tricked-out, expensive 1911 with a match trigger.
I like to try and keep things simple. Sometimes people are too caught up with gadgets. For example, you can get an AK-47 semi-auto style rifle and put a scope on it. The AK-47 rifle does not have great long-range accuracy, so I don't see what value a scope has for such a rifle. I am not knocking the AK-47, I am just saying that gadgets will not make it more accurate.
However a holographic sight would make it more "shootable" in an urban battle scenario. Take a look at pictures of our troops in the cities, towns and villages of Iraq and Afghanistan. You'll most have some kind of holographic optic. There's a good reason for that. It will apply to an AK just as much as an AR. They aren't in general cheap, but there are less expensive versions which would likely be fine for an AK.