We really want to give as much as we can to premium members. I think the coolest thing about membership will be experiencing all the new additions we add over time.
There seems to be some agreement on price.. it needs to be very inexpensive. Basically we want as many people as possible to become members so it has to be very affordable even to those without jobs.
The core thing to remember is that by being a member you are showing support for our site. Our ultimate goal is to have a staff member or two working full time on the site. Let's see if we can make that happen.
UPDATE:
I just added in basic web hosting. You won't be able to execute scripts, but it will provide a way to have your own site on the gamedev.net domain. You can also host files for your project or for inclusion in your developer journal. All that stuff will go down on members.gamedev.net. My journal also has a shorter url through there.. http://members.gamedev.net/tanczos/journal/. Right now I have the disk space quota set at 25 megabytes.
Annual fees for memberships work great for non-profit organizations and may also work well for GameDev.net. I'm a member of the Institute of General Semantics and the CSICOP paying $20 yearly for both. Of course, they don't provide as much Internet content as GameDev.net does (and they're not directly related to games), but I'm reasonably--not absolutely-- certain the cost of producing quarterly journals for 800+ members, etc., far exceed whatever costs of GDNet+ Membership bandwidth.