Well, I don't know about core picking, but it is safe to say, that this late in the stepping game, that you could get one of the coveted AXIA, AVIA, or that other 5-letter one without having to pick it. I would assume that by this point, most of the cores coming out of Dresden are one of those three, and that as long as a vendor has a quick stock turnover, you'll get one. Now, I have heard that you can ask vendors for a specific core, even online vendors, but I think that they will only do that on OEM CPUs, not retail.
Now, as to retail vs. OEM. With OEM, you get a CPU and a vendor warranty, usually 15-90 days. What it covers is dependent on the vendor, but it is safe to say that killing the CPU through overclocking is not something that is covered. With retail, you get the CPU, a 3-year factory warranty, as well as a HSF that works really well, but is a tad bit on the noisy side. Now, if you are overclocking, I'm sure a few extra dB of noise is outweighted by the extra cooling it provides. Plus, if that fan dies and your CPU fries, AMD will replace it, since it's their parts (hint for if you fry it doing something else). So, I would go for the 1.33 retail... but if your serious about getting the best bang for your buck, and are going to overclock it to the max., I'd go for a 1.2 retail. That way, you can still get the same overclock as a 1.33, but save money.
-SammyBoy
Putting his foot in his mouth since 1982!