www.DigitalPoint.com is the best I've found and visit several times a day! I also keep up with www.DNforum.com and www.SitePoint.com Recently acquired www.WebBrainiac.com and love watching it grow!
erm...for certain topic, i recommend, http://www.associateprograms.com http://www.conqueryourniche.com/forum/index http://www.bloggerforum.com/index.php
DP is good but to be honest, if you have a web programming question, you'd be better off going to SitePoint . If I wanted to look about Arbitage for eg, (do a search on DP for arbitage to see what I mean), I would probably head off to WickedFire who despite their very offhanded manner have many excellent threads on Arbitage. Just a thing to note, NEVER limit youself to one resource forum.
Yeah, it's too bad they don't have a higher quantity of all those quality posters. :| Unfortunately, higher quantity usually means that the low quality users even out the spectrum and the high quality ones aren't as visible anymore.
... just better: www.webdigity.com not only a webmaster forum but a community with CSS gallery, Scripting tutorials, webmaster directory and much more. (I'm not the owner )
I am a moderator at http://www.revenuesource.com which is geared toward affiliate marketing and other site monetization and have areas for SEO and development. At RevenueSource.com we award posters with RSBucks which can be redeem towards gift certificates and also you can use the RS Bucks to "buy" an upgrade on participating affiliate programs. For example, you can use your earned RS bucks to "buy" an extra 1% commission on top of the regular 4% commission I pay to FastFloors affiliates good for 6 months.
http://www.warriorforum.com/forum ! It's the best! All the big gurus are there: Mike Filsaime, Willie Crawford, John Reese...