Well here is my question in a bit more detail, I can get an i5 and budgeted towards it but was wondering if I needed it. I suppose I could do lower res but would want to upgrade anyway.
I plan on modding with realistic lighting and water, wet and cold, probably a bunch of others as well.
http://www.brillcom.com/intel-i3-3220-3-3-gig-system/
That is the system with an i5 and 1GB video card option taken.