As an update, this weekend I succesfully finished work on both Email + link verification, adding a Captcha to the registration process.
The Captcha I ended up using is a fullblown control. I did some tweaking to it in order for it to blend into the Register page (like expanding its inputbox's width, and adding dashed borders to it).
As for the E-mailing, I basically stripped the Profile bits out of the CreateUserWizard, added a sendingmail event to the wizard, and had the code for the event generate a GUID. I also ensured the CreateUserWizard would not automatically enable the users (a boolean flag).
The GUID along with the e-mail address are parsed into a link which leads to my activation page. A stored procedure, at the same time (for now I'm just using a localised Sqlcommand in the page, rather than extending the existing DAL class) inserts the GUID, the Email address, and the current system time into a temporary table.
When the user clicks the link, they will be heading to the Activation page, which contains two textboxes; one for the GUID and one for the E-mail address. On the PageLoad event, if the querystring contains the GUID and the E-mail address, the user will automatically be activated. Otherwise, this will happen when the user enters the values into the textboxes. (this is again done with a stored procedure).
When the activation is succesful, the user is then automatically refered to the rules of the site. :)
Hope someone else can use this info :)