I'll be watching to see how BlackBerry users react to the Pre reviews and early user word-of-mouth. I never expected many iPhone users to jump ship over the Pre, but the ability to convince BlackBerry users to move to the Pre will be important. That and the Pre's ability to attract people who haven't already purchased a smartphone but have, for whatever reason, not already bought an iPhone.
If Apple really wanted to ruin Palm's day, it would--right away--tell the world when its (presumed) new iPhones will be announced and perhaps tip its hat just a bit as to how many devices we should expect.
Bottom Line: Palm is now back in the market with a solid contender that is already playing catch-up in important areas like applications and is likely to soon lose whatever lead it may have in other areas.
From what has been shown so far, the real coming battle will be Google Android vs. iPhone and in that contest, it's possible that Google OS devices could come out on top. Palm, meanwhile, could end up being left way behind, provided Google can do a better job of rallying developers than it has been able to do so far.