I think 939 is going to be around a lot longer than S754. The fact that AMD is putting out S939 Semprons proves this. We saw this with AMD discontinuing Socket A Semprons in favor of the 754s, and it won't surprise me that once the Semprons get ramped up on 939 that 754 will start falling by the wayside.
It's true that M2 is going to replace 939 as the premier platform next year. However, even with 939 being relegated toward the "lower end", you'll still have a lot of choice. Throw a Sempron, A64 or X2 in there down the road and you can get a lot more life out of your system.
754's pretty much dead. I think buying legacy technology such as AGP and stuff like that are a waste ... especially if you're interested in "future proofing" ... if there is such a thing.
JMO.
Super