I agree.
Case - unless you are not fussy about noise and look/feel and decent case is worth it. Especially if you are changing bits and don't want cuts from sharp metal. 2nd hand is great though if you know what you are buying.
PSU. Cheap ones are generally noisy (if not to start with, later when the fan bearings go) and a poor quality PSU can cause all sorts of reliability problems that are almost impossible to diagnose. Personally I would not get 2nd hand here - too much chance it is being sold off because of issues.
The stock CPU fans are generally ok but not particularly quiet.
Processors, I have used both AMD and Intel. Not much in it although in the past I have found AMD gives you more bang per buck but Intel perhaps slightly better performance and lower power. This might have changed though.
Mobos- Never had a problem with any of the big names (eg asus, gigabyte, MSI, ASrock). Ditto memory, I tend to use crucial but have used Kingston, Corsair, HyperX with no problems.
Hard discs- the only problems I have had are with Seagate - I tend to go for WD nowadays (green for general desktop stuff, red for nas) as they are quiet and fast and I have never had a problem.
I have also used samsung SSDs a couple of times (the 850 evo) and they appear to perform well.
For graphics you will probably be fine with the on board adapter for general stuff (including photo editing) but I have used both radeon and Nvidia. I've had more problems with radeon but I suspect that is as much driver issues as the actual hardware.
Everyone will have their favorites though. Just avoid the generic stuff just because it will save you few pounds. This is where the likes of ccl etc have the advantage - they will have plenty of experience of where going cheap is a good idea and where it causes problems.