I am going to comment from the other side being a player of evil characters.
From the evil point of view actually associating with goods is in general something to be desired, though a dangerous undertaking, how else can you corrupt them or bend them to your designs if you do not have some dealings with them ?. There is also a degree of satisfaction in fooling them into thinking you are really not that bad while busily plotting there eventual downfall (evil laugh).
Also in some ways paradoxically it is far easier to deal in a business sense with an honest and honourable goodie than with other evils who in general cant be trusted as far as you could throw them.
What i find more interesting than alignment is the more black and white divisions along race and faith lines. While playing a Drow I have major problems having any dealings with an elf no matter what there alignment. And faith certainly places limitations on who you can deal with, a gods expressed likes and dislikes should reflect very strongly on there worshippers.
I also strongly back the IC consequences for IC actions idea. So if as an evil you want to hang around Waterdeep openly showing an evil symbol expect to get trouble up to and including an IMM bringing Blackstaff to life to say hello.( I have seen that happen once and it scared the pants off me !)
Duranamir the Drow who is definitely evil