It's excellent at stock if you consider performance from 2009 excellent.
Uh, my 6300 suits all of my needs at stock, it is never slow. Great multicore performance too. It performs quite nicely as a media server. And as stated before you'd be selling yourself short if you think a dual core CPU is going to be future proof. Multicore (as in FX 6 or 8 core, has clear advantage over any dual core, i3 or otherwise) + offset single-core performance with a good enough GPU and you have what you need. And if you are budget-oriented in your build, you are saving money by putting basically another $120 or so towards a better GPU that you would have instead been spending on, say, an i5. Say you really want a SSD too, this again helps you save money. If you are going to cheap out on the CPU a bit you want something that is still going to give you solid performance, and the FX series does just that. Despite lackluster single-core performance the overall strength of the FX series is indeed impressive given its age and price; it holds its own, and it isn't going to bottleneck future GPU upgrades. Hard to complain about that, again,
given its price (particularly the 6300).
If you have more money and don't require a budget build then yeah, by all means get a Xeon/i5/i7, it would be foolish not to. Or if you want get the most expensive board and sophisticated cooling for your FX chip and OC it like crazy; kind of silly but if that floats your boat, go for it. Either way the FX series is probably the best bang for your buck for a budget build because it doesn't come up too short if you have the right GPU, and really for any multicore app/process in general it is still quite impressive.
Really getting tired of the whole "AMD is garbage" mantra. You really can't go wrong with the FX series. If you want something better, spend more money -- but let's not act like there's no reason whatsoever to buy these CPU's.