Exchange Server 2013 Implementation

You can't migrate directly from 2003 to 2013. You need to migrate to either 2007 or 2010 first (I recommend 2010).

1/. The sizing all depends on your user base. How many emails they send and receive a day, the average size of those email and the size of their mailboxes. Microsoft has a sizing calculator I would recommend. Otherwise I am just guessing for you.
http://blogs.technet.com/b/exchange/archive/2013/05/14/released-exchange-2013-server-role-requirements-calculator.aspx

2/. The best redundancy would be four servers. Two servers acting as a CASARRAY and two servers acting as a DAG for mailbox redundancy.

3/. Software licenses depends on what you are going to accomplish. There are Standard and Enterprise Exchange Server licenses. The only difference here is the number of database you need and for 200 users I would say Exchange Server Standard is the way to go. There are also Standard and Enterprise USER CALs dependent on the features you need. If you need archiving for example, or, unified messaging. Standard CALs most functions. You world need 200 USER CALs and an Exchange Server Licenses depending on how many servers you go with, and any base OS server licenses.

4/. Are you referring to the Active Directory Connector? Shouldn't need this.

5/. I use Symantec Backup Exec 2012. R2 will be releasing soon and that will include granular recovery again.

Cool article on CALs for 2013 as well.
http://office.microsoft.com/en-us/exchange/microsoft-exchange-server-licensing-licensing-overview-FX103746915.aspx

thanks a lot diggisar, very useful tips. by the way we will go with 4 servers for exchange standard version with standard cals for 200 users.

considering the high availability options shall I opt VMware or hyperv is enough?

I've done quite a few on VMware ESXi without any problems. It is recommended you assign a raw LUN for the Exchange DBs, but I have seen people successfully use a datastore VMDK as well for smaller environments.

I have not personally tried Hyper-V, but being another Microsoft product you would hope it would work as well as VMware. I hear Hyper-V 2012 is a huge improvement over 2008 as well.

thanks a lot. iam clear now with the above. I need to invite the partners for quotes for the above.  in case if you think that we need to consider apart from above kindly let me know.

Hi Kurajesh. I didn't quite understand the last question.

i meant any other points to take care apart from the above points discussed for exchange 2013 implementation

Thanks a lot diggissaur. Very useful tips.