Supporting multiple screen sizes???!!!

Sorry but after reading the "Supporting multiple screen sizes" article, I can't find the best size for my project.

I want to make online game on my server and my project window size is 640 * 480 - Letterbox scale.

Is this good?

Is't better to make a short cut for all user's and make a list of the best sizes for the project's.

Like this:

For online games go for this options : 111*111 - ........

For I pad games go for : 111*111 - ......

For mobile games : 111*111 - ......

For export games : 111*111 - .....

etc

Best Regards to all

Sorry but after reading the "Supporting multiple screen sizes" article, I can't find the best size for my project.

I found this Article very helpful because he compared various devices/marketplaces.

And what to do with that info in regards to best sreen sizes

You must have missed the start of the article. The aspect ratio is more important than the actual size you use, so there is no specific list of actual sizes that are most appropriate, only aspect ratios. And the aspect ratios to aim for are 4:3, 16:9 and 16:10.