How Much is Too Much? Where is the Value in Attending Conferences?

After exploring for a while the  Consumed to Thrifty thread, I thought it could be useful to see how this applies to picking which conferences and events are worth attending, what their value proposition is.

Have you felt at times like your time and money would have been better used taking a vacation instead?

Therefore I offered a session looking at this topic during the Open Conference part of Web 2.0 Expo New York (September 16-19).

What justifies attending a conference, an event?
How much is too much as far as price goes?
Does the time and place plays a role in your choice?
Is face time with people you have only had contacts with online the best part.
Where are the best spots to make new connections, the coffee line, lunch break?
Have you felt that your time and money would have been spent better if you took a vacation after attending an event?
Which event? When? Where?

Related: Just Over 50 and Not Dead Yet and From Consumed to Thrifty