How much memory should I purchase?

Hello

I'm considering buying a Dell PowerApp.web 120 for a start-up shared hosting project. I'm looking to offer many features including ASP, PHP, and JSP which happen to be more processor intensize then static page requests therefor I'm going to go with a dual processer solution([2] Pentium III 1Ghz). I plan to purchace (3) 36 GB SCSI hard drives as well. What my questions are is first how many accounts do you think I can squese out of this server (dealing with 50MB, 100MB, 300MB, 500MB accounts) taking into consideration processor load and second how much memory do you think I should purchase for this server in relation to my goal of filling it as much as possible (max mem capasity is 8GB)? I look forward to your opinions. Thanks!

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