I know this must have been discussed somewhere before but I am debating between a PPC unit and an Intel (both Macs). What concerns me is that some of my apps and shareware will eventually go native Intel only and eliminate PPC architecture. I read something the other day that impressed that on me. Is there any need to worry for the next 2-3 years or more? Is there any patterns being set now that point to that possiblity of no more PPC support?
My non-technical opinion is this. There are tons of non-Intel machines out there, even some with Applecare that are or may be warrantied well into 2009 and even 2010 (They are still selling G4s and G5s on AppleStore's refurb webpage). I don't think they are going to drop support for these machines for at least the next 3 years. Now there are some Apps like the Joost Beta or Adobe's music recording program beta (I can't recall the name) that only run on the Intel platform, so there may be little or no support for PPC for these Apps or other professional Apps in coming years, but I would say that the Intel machines at that time will be l'ordre du jour because they will be much faster than what we even have today.
I have an iMac G5 which is warrantied until Nov 2008 and I am looking at selling and buying the last 17-inch Powerbook G4 model that can be warrantied until 2010, because I found one at a good price. My main concern has more to do with price drops on the Intels since most are due for an update in coming months, and maybe as early as June (re: new LED screens). I remember when the Core 2 Duos came out, I had corporate pricing of $1389 on the MacBook Pro base model.
So my 2 cents is, I think you're safe for 3 more years, but the prices of the existing Intel machines will be very interesting on product udpates, if you can afford to wait.