How much is it worth?

In my position as "The bloke in the office who knows a bit about music", I was today approached by a colleague who told me that whilst clearing his loft out at the weekend he find a stack of his old vinyl.  "If I give you a list", he asked, "could you tell me how much its worth".
"OK" said I, but don't go expecting a fortune.  We're really talking extra pocket money at a Car Boot Sale, rather than a feature spot on The Antiques Roadshow.

He didn't believe me.

Protests included:
"I've got the original Band Aid single" - so have I mate, and 3 million others (in fact, I think I've got 6 copies (for some reason?))
"Theres a couple of Beatles albums" - from the description they sound like 'Rock n Roll Music' Volumes 1 & 2 on Music For Pleasure
"What about 'Thriller', its an original copy so must be worth something, what with Michael Jackson dying and his doctor being convicted"

Every half-hour or so he'd come past offering a new "surefire money-spinner" (final offering was an original pressing (his words not mine) of 'Bat Out Of Hell').

I remained composed and politely said: "Bring me the list tomorrow, and I'll have a look".

I'm expecting the usual Charity Shop staples of Paul Young - No Parlez and The Cars - Heartbeat City.
Who knows, might even uncover a diamond in the rough.

Bugs me though - just because records are old, why are people convinced that it must be worth a mint?

EDIT: "I have in my hand a piece of paper" - its taken a couple of days, but I now have the list.
Pin Money or Pension Plan? - You Decide

Link to List: Records Found in Loft