Ok.. I did not even read any of the other posts on this question, but I will when I am done writing this.
I have been a computer repair tech for the past 12 years and have seen the best and the worst. I have also been into video/photo editing for most of that time. Here are my suggestions based on my personal experiences.
First suggestion..
DO NOT BUY A LAPTOP FOR PHOTO/VIDEO EDITING. People who do this are asking for punishment.
2. Laptops are 1/3 slower than desktops with the same stats.
3. Laptops get hot and die.... and are simply not made for this type of work.
4. Laptops are expensive to fix when they break down
5. The hard drives on Laptops DO NOT LAST. The reason being is that Hard drives are not meant to be moved about and jostled around, it will cause damage. I can not count how many laptop hard drives I had to do data recovery on in the past 6 months, and believe me... data recovery is expensive.
6. Laptops are very proprietary. All the parts are on the MB.
7. Laptops are very limited when it comes to upgrading them. Usually you can only upgrade the RAM and the Hard Drive.
Laptops are nice to have, and if I were to buy a new one I would not buy the highest end laptop nor the lowest end laptop. As far as brand and reliability, I would buy a Lenovo, or a Toshiba over any other brand out there.
If you buy a laptop... GET THE EXTENDED warranty, but remember that this will not cover data loss for a failed hard drive.
Why I would not buy a MAC:
Now let me first start off by saying that I don't think MACs are bad computers, because they are great systems.
1. They are very proprietary when they come to parts for repair, as well as very expensive. If they break, you might as well buy a new one.
2. There is NOTHING a MAC can do that my PC cant..... even when it comes to running MAC OSX, but I wont get into that.
3. There is a TON of software out there that simply will not run on a MAC.
4. People that say that MACs are better when it comes to video/photo are full of crap. They havent experienced a well built PC.
I would NOT buy a branded Desktop PC.
A few years ago I might would have, but now most branded PCs are proprietary when it comes to parts.
Proprietary parts are expensive and usually have to be ordered when it comes to replacing parts.
Here is what I would do. Find a good, reputable computer shop in town and have them build you a custom system. Let them know what you will be doing with the system and if they are a good computer shop, they can tailor one to your needs. A good system for photo editing should run you around $1700. Now, if you shop yourself and know what you are looking for, you can piece one together for about 3/4 of the price. The system I am running now I put together myself. It ran me around $1400 for everything, but if I were to have a shop do it, it would have cost me over $2500. It will out perform any MAC you throw at it and doesn't even flinch when I open photoshop cs3 along with 10 other programs.
I would NOT use Windows Vista... for obvious reasons...
I apologize if I stepped on anyone's toes.. but I'm a tech and I speak from experience. Heck, I work on computers that people like you guys use, and see all the good and the bad.. and the worse.