I have been faithful to Intel until Intel D came out.
It's not really about being faithful to AMD or Intel. It's not about AMD vs Intel. It's about the best performance. And the most we can actually do is tell you - and this is no flame - that overall, Core 2 Duo is the one who actually deserves to be on a system labelled with "dream". This is simply a fact, and it
is an inconsistency in your initial post.
The other inconsistency here is the upgradability. Right now, from what we know, AM3 CPUs will be backwards compatible with AM2, but will probably operate at less than optimal speeds. And Intel's future Quad-core CPUs will all run on most quality motherboards supporting C2Ds. So the upgradability probably won't be that much better! Keep in mind that according to what we currently know, both platforms
should support the next quad-core processor, so upgradability isn't looking as if AMD has an advantage. BTW, Intel's quads have already been tested on many current mobos too, which is an extra guarantee that that upgrade path exists for Intel.
... in any case, both these companies always tell us that their platforms are widely upgradable until they suddenly state otherwise because of some pin/power/specs/features revision that they weren't really planning but that was needed...
Of course, it is your decision and you can buy whatever processor you'd like. But those higher-end A64s like the 5600 and 6000 are basically paper launches and knee jerk reactions to C2D, and their availability is very limited.
Not even review sites have seen an A64 X2 6000 in action, not even those taiwanese ones, so you will probably have A LOT of difficulty in finding one such processor. You could settle for a Windsor-core A64 FX-62, at 2.8Ghz: it might do 3.0Ghz (but not beyond) and it comes with an unlocked multiplier.
Sorry if I upset you in any way with this post...