My supervisor is looking to get me a MacBook Pro and he said to just spec it out and he'll get it. I work in IT doing client support for faculty, students, etc. I'm not working with videos, photos or audio or anything of that nature. However I will be using the MBP to run different OSes for testing and for troubleshooting on Macs. Hopefully that gives you an idea of what I'm going to be doing with the machine. Anyways, I'd like to make this machine last me at least 4 yrs. I'm looking strictly at the low-end MBP for 13/15" models. I know the 13" has C2D w/ 3MB L2 cache while the 15" has the i5 w/ 3MB L3 cache. Would the i5 be worth it for future purposes (longevity)? Also, I noticed the 15" has 2 built-in gpu. Is there a noticeable performance advantage to this? Would it make any difference/help if running a virtual machine? I'm thinking of running at least Windows 7, XP and possibly Server 2008 R2. Generally not at the same time mind you. Lastly, I know that the MacBook Pro comes with 4GB of RAM standard. Should I be looking at more memory here? I want to be able to justify the specs to my supervisor since there will be at least a $600 difference between the two models.