I know this is old and I know I'm barely into this myself but you might want to check into jQuery if you're thinking web based and are leaning away from flash/java. It's very efficient and a lot of games are starting to come out with jQuery as the basis for the engine. By default it has ajax commands built into it and it's highly, if not insanely, customizable. Best of all it's JavaScript so it's as real time as you want it to be on the web browser. (Done right, you don't even need anymore than a single page to run the entire game though that can be difficult to do.) http://www.jquery.com/
Java is good for creating 2d and basic 3d games but not many really prefer it anymore. Most use flash because it simplifies the process of putting images on the screen and making them interactive.
http://www.gamedev.net/ is a website I use frequently for game development questions though they tend to stick with the industry standards for game dev (e.g. C++, DirectX, etc...).
Hope this helps.
Dan