you want to create a website which have some forms (including image accessories,info etc...) online obligations , monitoring system along with other features that could add later . count of customers maybe a lot more than 50,000

I am using wordpress to build up regular websites but i am afraid for doing things within this project because i'm not sure how optimize is wordpress for top database usage (and page rendering , bandwidth usage and ...)

My options (individuals which i know) are : wordpress drupal pressflow agilitycms

writing php+mysql codes on your own (or using framework)

Yes, it maybe unrelated but exactly how good is by using ASP.internet rather than these ?

(sorry for my bad british) thanks

ASP.Internet provides extensive capable options to get this done. The most typical ones (a minimum of during my world), are Kentico, Umbraco, and DotNetNuke. You will find a lot of others.

You will find plenty of capable Content management systems systems to utilize regardless of what language you are searching at. Use what you are preferred dealing with.

Right. If you're preferred with PHP (the scripting language behind Wordpress and Drupal), you will probably become more comfortable making the key to Drupal. Pressflow is simply a fork of Drupal enhanced for particular needs (and you will find other forks from it -- all are really just Drupal and therefore are frequently the foundation for a number of Drupal distributions).