What I did was remove all the options (basically from the options separator down) and then, when they activate their membership, instead of going to the main forum page, they are taken to their edit options page. ( You can test this at my board -
http://board.tubescan.com/ )
You need to edit register.php, on line 514 - change it to this:
Code:
eval("standardredirect(\"".gettemplate("redirect_registerthanks")."\",\"member.php?s=$session[sessionhash]&action=editoptions\");");
I also created a new function in functions.php to accomodate this, as I wanted it to sit on the redirection screen for longer than normal to let people know where they were going and what they were supposed to do there, instead of just dumping them in their profile.

But you could do this with the standard redirect as well (as I have shown above).