Best practice Converting Cent OS V6.2 / V5.1 Postfix email server and 2003 AD_DS

Dear all vsphere convertor exports,

I curently install vSphere 5.1 (esxi 5.1 hypervisor and vCenter Server Appliance 5.1) in my newly purchase Cisco UCS 460 M2 High Performance Rack Server.

Now I want to convert all my Tower low in physical server into virtual vSphere server. I read vSphere convetor guide but still not confident to convert following server.

Cent OS 5.3 Mail server

Physical Machine : IBM System x3250 M4 2583

Raid : Raid 10 (300GB *10)

RAm: 4 GB

OS: Cent OS 5.3 + Postfix mail server + slave DNS server

CentOS 6.3 Web server

Physical Machine: HP Proliant DL 380 G5

Raid: Raid 6

RAM: 8 GB

OS: CentOS 6.2 + mySQL+ web Apache+

Windows server 2003 + Active Direcory + Domain Controller

Physical machine: Dell Poweredge 310 (tower server)

Raid: Raid 1

RAM: 8 GB

OS: windows server 2003 Active DIrectory

Windows server 2008R2 + MS SQL 2008R2 + Visual Studio v10

Physical Machine: Dell Power Edge R710

Raid: Raid 10

RAM : 16 GB

OS: windows server 2008R2+ MS SQL 2008R2 + Visual Studio v 10

I can poweroff server for cold Convert in Holiday / Night Time and other weekend but I want to know the best way how I can move all my physical server into VMware Esxi 5.1 hypervisor  so that all my server work well as they are working now.