If you like the looks of the old school bikes, look at a Royal Enfield 500 (formerly Lee Enfield)
http://www.enfieldmotorcycles.com/.
essentially it is a 1950’s motorcycle still in production today (some improvements). Single cylinder air cooled. Very simple to work on and repair yourself if that is your want. Handles rough terrain very well. Will do highway speeds. These bikes have ridden all over the world.
But, it does have a number of draw backs, it’ll leak a bit of oil, handling and stopping are not like a modern street bike.
If your goal is simply a bike that works, there are better choices, but these Enfields are just plain neat imo.
On the topic of better choices, look at “street fighter” ninja 250s. Basically you pull off the fairing (usually due to damage), through on a regular headlamp, signals, mirrors, and instrument cluster, and you get a little bike that looks like any naked you want (through a simple round lamp on the front and it’ll look like a nighthawk, put a double lamp from a triump triple on it and people will confuse it for a street triple. There are tons of aftermarket headlights out there.