Advise on Server,softwares required !!

Hello,

        Iam looking to host a web based .NET application which uses MS-SQL as database. I need to what type of hosting should i choose.

1. Application Type - Billing and internal Operations
2. Number of users at a time - 100 to 300.


Hosting Types - Which is preferred ?

1. Cloud Based ?
2. Dedicated ?

Resources Required ?

1. What should be the Processor ? - Single , Dual , Quad or XEON ?
2. What should be Minimum RAM size.
3. Storage - 1 to 2 TB is sufficient ?
4. What should be Firewall preferred ?
5. What should be the Best Antivirus to protect Server ?
6. Which MS-SQL db server is preferred ?

Questions regarding Fail over -

1. How it should be managed ?
2. In server level or the database or application level. Please advise ?


Best Dedicated / Cloud servers as per your experiance ?

Thanks !!