Well, both EDN and user forums are really the best source of information. Yet, I must say, which is not much pleasure. For new APIs built upon ArcGIS Server, it feels better on resources.esri.com - at least there are many samples, and there's also community part (that rocks). Things are going better, I guess.
Do you have some contacts inside ESRI? For me, as an employee of local ESRI distributor, there is always possibility to write an e-mail to ESRI support, and from time to time I can really get back some valuable information. Unfortunately, this is time consuming.
As uberjumper has noted, most valuable are ESRI people themselves. During our user conference we always try to get as much information as possible from our visitors from ESRI, because - at least - you can get contact to person who can help you with particular problem, if the visitors doesn't know. And also, there are many people over the world who solve (or solved in the past) similar problems like you, StackOverflow perhaps becomes more and more important. :-)