Artista said:
On that, is a four core CPU or two core the lowest one should go now days?
It's not quite that simple.
In general, you should value performance per core over number of cores at any given price point. Performance per core is something that all applications can take advantage of, whereas applications need to be coded to take advantage of several CPU threads. At this time, the number of applications (including games) that can use more than four threads are in the minority, while many still use only one or two. The practical implication here is that for most people it's better to get Intel i3 over AMD FX-4000 or FX-6000 series and Intel i5 over AMD FX-8000 series. Beyond i5, the only way to increase performance is more threads (i7).
Whether you should get an i3 or an i5 - or a Pentium or an i7 - is a matter of budget. The i3 is actually hyperthreaded, so its two cores generate four threads which makes it around 75% as fast as a true quad core (i5) in applications that use at least four threads. At the moment, the lowest you can get an i5 for is $185:
i5-3470 (after promo).
In a year or two I would probably upgrade my CPU to a Ivy Bridge or whatever the latest CPU that will work in the LGA 1155 Intel socket.
Not a bad idea. You can probably find plenty of used i5 Ivy Bridge CPUs for sale in two years when Intel releases Broadwell, the die shrink of the upcoming Haswell architecture. I'd say most hardcore users tend to upgrade every other generation.
How does the board choice up top look? (ASROCK PRO3 $84)
If you buy an i3, get the Z75 Pro3 since it supports overclocking - that way you can get full advantage from a used i5-3570K by coupling that upgrade with an aftermarket heatsink. If you get an i5-3470, I'd recommend
Asrock H77M for $70. I would go with i5 and H77 myself... In two years, I would want to upgrade to a Broadwell i5.