for holsters.. it really depends on what your primary purpose is.. and what youre going to be doing all day...
personally, I prefer mid to high ride, belt slide, level 1 retention, straight draw, leather holsters, of high quality... I find that this brings the best combination of concealment and comfort.. I only wrap my pistols in Kramer horsehide... but I will admit on the front end that it is spendy.. and that there are other, lower cost options that will serve you just as well..
A lot of guys prefer appendix carry.. A lot of people prefer IWB as opposed to OWB.. nothing wrong with those choices... everything is a trade off.. one option might give you a little more comfort.. one might give you a slightly faster draw.. another might give you a little better concealment.. etc..etc..
for me.. Ive been carrying a gun just behind my left hip for over 20 years.. when I was a cop I wore a mid ride duty belt holster on my left.. and later a high ride concealment holster when I worked assignments other than patrol... the only exceptions were when I worked as a SWAT cop, a soldier, and a contractor, where I wore a left side drop holster... so.. for me.. having the gun in the same place it has always been (left side, OWB, slightly behind the hip) is a given... its where my hands naturally go when I hit condition orange... there is no thought or hesitation.. it just happens...
all that said.. you have to find what works for you.. how do you dress? what pistol are you going to carry? what activities are you going to be doing on a typical day when you are carrying? will your range allow you to practice/train draw strokes? if so, do they limit where the pistol can be (many wont allow crossdraw, appendix draw, off person draw (man purses, etc..), shoulder holster draw, etc..)? etc..etc..