When you get into the SLR/DSLR world, you're hitching your wagon to the lens system far more than to the camera body and you should look at the whole purchase from that perspective. Even with the best camera body, the glass is still going to be your biggest investment.

Since your current lenses will fit the Alpha, the only real question is "will Sony be releasing another DSLR in the pro area in the near future?" I'd say that the answer to that one is definitely "yes" even though we haven't heard anything about it yet. This will ALWAYS be the case with digital cameras, as it is with every other type of electronic gizmo. Don't worry about it. If the Alpha gives you something you'd enjoy, then get it. If there's something about it that bothers you, then don't. Whether you do or don't buy, there will be a newer (and probably better) model out within a year. But lens mount systems will be around for 20 years or longer. That's what you should be paying attention to.

In any case, you should have a lot of fun deciding!

As a Minolta shooter (since my XG-1 in 1980) I have hesitated to move into the Dslr world. I bought a Dimage EX in 1999 and I guess it was okay for the time but cost a bundle. That camerea did not make me want a DSLR any sooner than later. So I stuck with my 500si until the Alpha came out. I am very happy with it and Sony's support which I have already had to use. That was because the first Alpha was bad out of the box (a corrupted firmware problem), so Sony said return it and get a new one. My older AF lenses work well on it, including a 24 (36) mm Sigma f 2.8 Macro. The Shutter response is a quick as my SI and the auto focusing, even with the older lenses is much better, since I can choose the focusing area. As a 7d owner I think you would be pleased with the enhacements that Sony has added to an already good camera. But I have a question. I want to purchase a wide angle zoom. I am looking at the Sony 11-18 f5-5.6 or the Sigma 10-20 f4-5.6 EX DC. There is about a 150 bucks difference in price, the Sony costing more. Is the Sony lense worth the difference? (I believe it is.)