i5, SSD price and longterm maintenance/performance, USB3.0, "300" or "5xxx" vid cards . . . I guess you could wait forever.
If I could wait for i5, I would. If not, you can deal with the rest of the issues by going i7 or AMD, and not investing a lot in disk (ie no Velociraptors) or vid card (get good enough for now, not overkill). Add/replace next year. IMHO, you won't really miss USB 3.0.