pcb standoffs?

Really depends on where you are located and what you want to buy. Search by "threaded standoff". They aren't specific to the electronics world, so don't just look at electronics shops.

Typical online places are supply houses like McMaster-Carr or parts houses like Mouser/Digikey, etc. Local places like Radio Shack, Frys, Microcenter, etc might have them too, but expect to pay a lot more for them there.

They come in all shapes and sizes, materials and so forth. I typically use 1/4" long aluminum ones with 4-40 threads.

I buy them from McMaster:
www.mcmaster.com/#standard-threaded-standoffs/

Here you go: 
www.mouser.com/ProductDetail/Keystone-Electronics/8440C/?qs=%2fha2pyFadugFbQDOM3RfE739cGsm%2fNlrJls14hDapNY%3d

And use these screws:
www.mouser.com/ProductDetail/Keystone-Electronics/9300/?qs=sGAEpiMZZMsQtlBhqKq43ecQHa8lxJka

Go to Lowe's and buy a bag of #6 lock washers in the screw/hardware aisle and you're set.

I don't like metal standoffs at all.  If by chance the screw or washer that's holding your pcb to the standoff rubs through the pcb into your ground plane, you've now got a ground loop.  I prefer nylon or insulated.

That's not necessarily true at all.  Ground loops happen because ground traces/planes are too high impedance to return the collective currents to the supply.  Doesn't necessarily have anything to do with grounding to a chassis or not.  If a ground loop forms from grounding to the chassis, it only shows deficiency in the PCB layout, not from simply using a chassis to ground the board.

Generally speaking, adding a ground plane, whether in the PCB stackup itself, or using a chassis as main ground can be very beneficial if done correctly.  The problem is that not a lot of people at the DIY level understand ground current physics.  Even a lot of fellow electrical engineers I know misunderstand grounding methodology as it's not a trivial matter at all.

It's even more fun when you get up into the RF range where even your ground traces/planes end up with standing waveforms on them and you have to integrate full clamshell shielding and design around the waveguide effect that it creates.

Loads of fun!

Agreed.  I always run the main ground plane under the top plane, AKA microstrip transmission line arrangement.  it couples the EMI to tighten the fields as well as gives a good solid ground plane.

You can cut under resistors and such, but at higher frequencies you have to be careful because cutouts can cause discontinuities which can alter the current flows and also form filters known as DEF (Distributed Element Filters).  A cutout in a plane or trace can make a low pass filter at low Mhz frequencies and above.  Not a big deal for audio, but if you have any heavy RFI filtering happening on the board (for ingress or from microprocessors on the same board) you can have issues with current eddies which show up as clock/signal spurs at strange places on the PCB.

Cutouts under parts also create impedance discontinuities.  If the goal is working with higher speed signals, like clocks for micros, or RF in general, you typically want an impedance controlled transmission line so no reflections happen which can couple into your other analog portions, or because reflections at high levels can degrade waveforms through partial waveform nulling.  Having cutouts without considering impedance control can cause anomalous reflections and spurious signals which will always find some nice quiet analog traces to infect! 

does raising the resistors off the board  a bit combat the capacitive coupling effect? or no because the leads come back down?

the capacitive effects between resistors  and ground plane on top layer are however very small.
I would see with more attention the capacitive effects between tracks and ground plane that are generally much higher those of the resistors. 

you have seen probably small tracks

for example in audio power amplifiers you may see much bigger tracks.
Inside power amps, large and long tracks may be a problem if ground planes are used there.
(for the high current handled inside them these big tracks are required)
Just doing some calculations. For this reason (and other ones) some amp designers avoid to use ground plane inside audio power amps.

Most of my work is mic or line level audio. For power amps, ground planes are not a great idea unless you carefully cut and direct return ground currents away from other areas. A star like redirecting of return currents is going to work better than a general plane for everything.

There are all sorts of design details involved, including the return currents of psu bypass caps. Further into the details are amplifier chips with internal references to either rail, that can also affect ground returns. You end up collecting all the data you can, make the layouts and test. That's why you see revision 2, 3 or more on pcb's that continue to evolve from the designers.