I can only agree with some of the sentiments written here ie 'Just buy what you like' ...that's what I do. I start by looking through loads of record boxes until my fingers start to bleed and then proceed to put the records that I am interested in to the back of the box (to get later on) Then I go back later on to find that they have all gone or been mixed up again.
Another good place to look is in your own sales box. I was looking at Pat Brady's website where he had got a record up for sale for £50. The same record had been in my sales box for about 8 years for a £5 for the other side. I quickly flipped it over and thought 'this ain't bad, I'll have that' So what's the moral of this story?.....I don't know perhaps someone could tell me...