You'll be fine with the i5. Depends how long you want to future-proof your computer. i7 may add a couple years to its lifespan.
I guess a point to consider is whether most people use the same computer until it no longer works for them, or do they upgrade because they are tired of the same ole same ole after a couple years.
I would bet that most who buy a new computer do so because of the new features offerred on the new computer, and bnot because the computer they currently own no longer suite their needs.
Just my opinion, and I already know it's worthless!