Bluetooth, is almost a standard feature, and I doubt you will find a head unit with nav that doesn't have it. I would suggest searching through Cruchfield.com . They are a popular recommendation, because they: can help with everything you need for your setup, I'm pretty sure they will price match (but are usually right at the competitive price), they have a lot of information on their easily navigated site, and they offer support on everything they sell for three months.
To keep it simple I would say avoid an amplifier, because it sounds like you don't need one. I would pick out your head unit first (which is usually dependent on someone's budget), then get speakers that match the wattage of the head unit (probably 22-50w per channel depending). Head unit is going to be anywhere from a couple hundred to a couple thousand. Speakers for a low wattage setup will be about $100 for two pair. If you look at a few NAV units, and are uncertain, read up on android auto or apple carplay depending on your phone. Just be aware of what it is, and what it does, and that might sway your decision.
Crutchfield will most likely include any harness needed to hook up the head unit (free), unless you are wanting to add steering wheel controls. There should be threads in here on that if that's a priority (or even down the road).
From here, I would say either fill us in with what the budget is, or what models you are looking at.
Just to throw it out there, if the budget allows it (probably $600-$800, or less for partial), and considering you like talk radio and not loud. You might want to add some sound deadening. You can just do the doors (for about $150-$200), and then use the rest for floorboards, or do the entire thing. It will help to quiet down the outside ambient noise, help make your music/radio more clear. Its the equivalent of sitting in traffic listening to your radio with the windows down, then putting them up to block out the outside noise. I did it and really enjoy the calming quietness I have the option to enjoy (and now usually prefer it).
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