1. There's a typo early on talking about the 540 and 545; should be 940 and 945 I think.
2. The i3 looks like a surprisingly valid choice. For primarily gaming, I hope I didn't simply waste money getting an i5/650 recently.
3. It looks like that L3 cache really matters.
4. I would really like to have seen the Phenom II X2 555 in this. I don't think it would have looked all that good, but would have given perspective on cache vs core count. A 720BE would have answered the same question, and probably looked a lot better doing it. Both are in the <$150 range.
5. Although I've seen bang/buck charts in similar roundups before, this time you can probably decide what minimum performance you want, then buy the cheapest one that gives it (but consider the multitasking question too).