When building links... given that most of links on the net nowadays are nofollow, if Google sees most of links linking to your site are do-follow, don't you think it will look unnatural? Is this a Google conspiracy, trying to make it easier for them to determine unnatural link building?
IMO it's totally unnecessary to chase a few nofollow links to make your link profile look natural. I've run a few sites through backlinkwatch that rank well for competitive keywords and some have very few nofollow links. I'm also not sure whether the majority of links are nofollow these days - certainly a lot of blog owners and SEO-savvy webmasters make certain links nofollow (especially comments), but many people are simply unaware of this attribute and therefore do not use it. I really don't think that having only followed links is a flag to Google - many sites could quite innocently end up with only followed links so it doesn't make sense to punish them for this. There are other ways to make your link profile more natural and I'd certainly recommend diversifying the type of links you obtain if you are heavily into link purchasing or you use grey hat methods.
there are other popular search engines beside google that can send you a good amount of traffic too. if the link is good, i would get it regardless of nofollow status
I always go for a few nofollow links just to make sure it looks more natural. Others say however that it isn't needed so yeah I am still in the middle.