I believe you are correct about something at last - you are taking crazy pills!
Quote: "The fixed number is supposed to tell us the CURRENT page not the TOTAL."
And why exactly is it important that the current page is fixed? - IT ISN'T!
While viewing a thread you cannot change how many pages there are in total but you can change which page to view, so, to have the current page fixed is illogical.
Quote: "What if someone accidentally changes the checkbox?"
Then the page will change and they will realise they have done something accidentally.
Quote: "They could quite easily forget what page they're on."
No they couldn't, because it says which page your on at the top and bottom of the page in the very message we are discussing.
Quote: "And what use is the Fixed Total number? If they wanted to see the total they could open the checkbox and see the last number in the list."
Surely any fool can see what is wrong with that statement.
Quote: "In your method they would have to change the checkbox before pressing "go""
Wrong again. In my method there would be no need for the 'go' button.
Quote: "It's either readability or usability. Personally I say make it more usable"
And there it is - clear evidence of your 'crazy pills'. How can anything be more usable if you can't read it?
My method is both usable
and readable.