I'm about finished reading Super Systems 2, and there is a point earlier on in the book which I'd like to hear a little more about.

pg 133 "If you average a big profit by calling, you aren't calling enough"

This section assumes you some how make it to the river with a vulnerable hand, and are faced with a bet or raise.

This small section talks about calling pot odds even when you know you're more than likely going to show a losing hand most of the time. They base this due to the fact that the one time you do call with the best hand will turn a profit in the long run. Now, this section seems to be talking specifically about Limit hold'em, but can this point apply to no-limit as well?

What odds are acceptable to call with, what you believe to be, the second best hand? 3:1? 4:1? 5:1? 6:1? never acceptable? What hands, that are vulnerable based on the community cards, would be acceptable? LP? MP? TP? two-pair?