Art Forums

www.conceptart.org - ConceptArt.org is a great place to see a lot of the world's best talent in illustration and concept art. There are a good number of industry professionals as well newcomers who post their work here.
forums.cgsociety.org - CG Talk is the name of the forums that are a part of CGSociety.org. It was and still is mainly a forum for 3D computer graphics, but has expanded to include a lot of 2D artists as well.
www.polycount.com - A great place to view work from people trying to break into the video game industry and established professionals too.
www.gameartisans.org - While newer than Polycount, and sharing a lot of the same member base, these forums showcase some great work as well.
www.wayofthepixel.net - The Pixelation forums are home to oldschool game/graphic artists that favor the pixel by pixel technique over newer styles. Often this art uses extremely low resolutions and limited color palettes, but still manages to achieve beautiful results.

Video Game Development

www.tigsource.com - The Independent Gaming Source is a wonderful site to keep up-to-date on news and events around the independent video game scene. It is a great promotional tool for small development teams, often containing articles on new game releases or info on games currently being made.
www.gamedev.net - GameDev.net is the perfect resource for news on the video game development field. The forums there are also full of information for beginners to more advanced skill levels.