That's a loaded question. Much of the link building today is centered around fairly automated stuff; getting links where anyone can get links, or using automated methods to get somewhat one-up links.
In terms of the old school white hat linkbait/link begging, that still works, just with a much more limited success. I wouldn't disregard it as a base, but I don't think it's enough on it's own.
My next link building campaign, to be launched very shortly, is going to involve some unique content-type stuff followed by some link begging. But the link begging is going to be secondary - I'm going to offer something of unique value to people with top quality sites - and then pull the ole' switcheroo - you want access to what I got? You got it, conditional on paying me money AND a link. No link for me, you can go pound salt on what I'm offering.
The 'what I'm offering' could be considered linkbait, but it's more than that because my potential link sources want the linkbait - it's beyond just 'i have nice content, so give them a link'.
In fact, I'm expecting to run some ads in industry magazines, saying 'you want this, gimme a holler'. Hopefully the phone rings.
Sorry that's a bit vague. But if you can find something that website owners are demanding or can use even if it's not website related! then you've got a case to demand a link.
And I continue to get my one ups. Had a guy from a local computer user's group come by to use some specialized equipment. He offered some payment, I declined. Then somehow the conversation turned to links and how that's my form of conversation. I'm expecting a link from him. I do as much of that one-on-one link building as I can.