As much as I'm a spec-whore and drool looking at all these new devices, if given the chance, I probably wouldn't upgrade. I'm still more than a year off from an upgrade, but I'm in no rush. All these phones have nice specs, but at the end of the day, my Desire is fine for me, and as long as ROMs are still pumped out for it, I won't be that far behind the curve as far as software goes.
I would love to have a tablet, but honestly, tablets haven't progressed to the point yet where I'm convinced buying one would be a wise investment. I disagree somewhat with the idea that they're a fad, and I do believe they will carve out a niche market, but at the moment they aren't going to replace either the laptop or the smartphone in many areas. Get back to me when it starts to get close to replicating the experience of a true computer. Because honestly my MBP isn't too heavy to use while I lay back and my Desire covers portability.