Deal for a Laptop for Home Office.

I need a laptop for my official cum home use (Would prefer Professional series).
I am thinking to choose from : Dell Vostro, Latitude or IBM Thinkpad T series with atleast i5 2nd gen processor and 15" display ( HD atleast). HDD I would like to have a 7200 rpm.

Any suggestions to find good deals like 30-40 % off on Thinkpads few months back.

I have a budget of 1400-1500 dollars.