My 70's P is heavy (but I like that), big bodied (but I like that) fat C shaped neck profile (but I like that), strung with flats (yes, you guessed it). Turn on any music show eg. Jools and almost every band will be sporting a P (I guess they have image).
Be careful about spending a shed load on one though. In my experience, there are many cheaper P's (Squiers especially) that may provide the same thing for a lot less cash. Just play loads and buy the one that feels just right.
LC