I5 or i7

i5 is quad core. If your apps are optimized of using multi threaded processors then it would be good to get an i7. Otherwise i5 760 still does the job pretty well. Also saves you a $100. With that you can get a better GPU.

First of all decide what kind of apps you generally use.

How many VMs do you usually run at a time? If you usually have 3 or 4 computationally heavy apps open at a time you will get a boost out of an i7, if you are only ever using one thing at a time then an i5 will handle things well.

For gaming both the i5 and the i7 will perform similarly so that wont matter too much.

The i7 series has hyper-threading.

There aren't any games that will make use of hyper-threading. In fact, the most cores a game currently utilizes is 3. The increase in performance from using 2 cores to 3 cores is not significant; about 10% - 15% depending on the game. Of course, if the game cannot use more than 2 cores then the improvement will be 0%.

If you know that the programs you will be using will take advantage of hyper-threading, then buy a i7 CPU. Other buy a i5 CPU.

I would get an i7 if you virtualize. Your system will have more power and virtual cores and you can give your VM's more resources.