Yes, don't buy it until you know it's compatible. I did my best to make sure it was, but I can't be sure to the point where I would have you buy it all until confirmed by a tech.
Edit: The motherboard I said was the P5K-V, which I forgot to clarify on. Since it's not there, I don't know what to recommend because then we'd possibly need different components.
As for the
CPU, there doesn't seem to be much difference between the two listed in the results. I'd go with the cheaper one.
I also realized I forgot to recommend a Hard Drive. For that motherboard I specified, I'd go with a SATA one, and other than that it's your choice what to buy for it.