I have been reading several posts on these forums about this subject. How about this...
Following on from Marcus's comments about a credit page, If the link went back to the specfic portfolio page for that client on the designer's site is that better than linking back to the root domain? If this is a good way to go what anchor text would you recommend [brand name] or [brand name | keyword] or [keyword]
Would that link still need to be a nofollow. As far as I understand it a nofollow is for a site you can't vouch for or trust implicitly, however as the website designer a link back from a client site could be a trusted link could it not? Assuming we have the client agreement of course