I need a straight answer.... is this overblown? I keep hearing one side of the argument that even a little can fry your mobo/cpu/ram/HDD, and the other side that people work on carpet for years and never once had a problem.
Generally speaking, If I touch the case constantly/while I'm touching other parts, will I be fine?
Touching unpainted steel surface on my case should be good even if there's no PSU connected, right?
Working on a marble table on hardwood floors is good?
I'm not wearing those stupid wristbands that look like death traps if some wiring goes wrong. But is the above good enough?
Touching the bare metal of the case is fine before working on your computer, and is a good idea/best practice. Also working on a marble table/wood floor is absoutely fine.
I've previously had bad static problems (due to my micro fiber couch) and at one point I somehow shocked my laptop, anyways it was fine from that shocking (even stayed on during the whole static shock fiasco).
However I might have just been lucky.
One more thing - those wrist straps would not be death traps, normally when you work on a computer it's completely unplugged from the wall (or should be).
So I would say what your hearing from both sides is somewhat true. Static shock can kill components easily, however they are still somewhat "tough" for lack of a better word right now.
Static electricity is a major killer to the tiny components that make up a motherboard, graphics card, etc. ESD can generate quite high voltages. Higher than the components can withstand. I'm usually too lazy to put on my wrist strap, but that would be the proper way to work on your system. As Chainsaw says, remembering to ground yourself occasionally to the metal case is a good alternative practice. I take one exception to his recommendation, however. I always leave my PSU plugged in (turned off, naturally). If your home or business has a properly grounded electrical system in accordance with the National Electrical Code, leaving it plugged in will provide a path to discharge any ESD to earth.
One other thing. You have the wrong idea about grounding wrist straps. They are in no way a 'death trap'. Why would you think that? There are no voltages greater than 12V DC provided by the PSU.
The wrist straps have a series resistor in them of about 1Mohm so even if you were to connect one to 240V you would be perfectly safe.
Electronic components when fitted to a board are resistant to damage by static electricity but it does not hurt to err on the side of caution.
A mistake that people often do is to forget that the computer is powered on if the power cord is connected and that damage to the computer can result if you plug in cards with the power cable connected.
I always make sure that I am discharged before working on my computer by touching a earth surface and I also avoid touching any part of the electronics.
Basically this is what I'm getting. Especially with the PSU. Does it matter if the PSU is plugged in or not? Steel case sitting on a travertine table in a room with hardwood floors. Is that not grounded/higher risk of damaging my parts?
In US homes that employ grounded neutral 120V AC power and with the use of modern ATX power supplies, the power switch (0/1) on the back of the PSU disconnects both sides of the primary line; the 'hot' and the neutral. It is shown here in this wiring diagram of a typical ATX PC power supply: http://circuit-diagram.net/wp-content/uploads/2012/04/3...
When the switch is opened, the only conductor that still has continuity to the inside of the case is ground wire. So all conductive surfaces of the case remain at ground potential. Some older PSUs may only disconnect the 'hot' side of the line. But the neutral is a 'grounded neutral' that is at ground potential and of no danger.