Wow that's lots to think about. Let's say I go to look at a new system. What should it include if my wish list is a larger nicer monitor and the ability to run CS4? I can take that list in and see what the computer guys have to offer. Can I get a new system with XP and avoid Vista? Thanks for the help.
My general advice on new systems is to buy what you can afford, even if its more than what you think you might need at the time. Reason being is that things are moving so fast, what you get today will be out of date tomorrow and software requirements keep increasing and you don't want to have to buy again next year if you can at all avoid it.
Dual core processors are pretty much the norm now, and quad cores are becoming more and more prevalent. Biggest thing here is the speed ratings and built in cache. Go for a faster unit with at least 1 meg of cache on it, if not more. That's per processor on the multi-processor cores.
Get as much memory as you can. Windows XP 32 bit will only handle about 3G, so loading up much beyond that will be useless as it won't be able to use it. If you end up with a 64 bit version of Vista, you can go nearly as high as you'd like, but don't go overboard. For what you will be using the machine for, 4G no matter what your OS is should be enough. I have never seen my machine use all the memory I have installed at any given instant. Make sure, though, that it uses dual channel memory. Its faster.
Any of the newer video cards should be able to handle a wide screen LCD monitor. Keep in mind the specs of the monitor you are considering, and make sure the card you get can handle it. I would also recommend a card with at least 256 Meg, if not more, of memory on it. it all adds up to letting that card handle its appointed task quicker.
I'm also in favor of the biggest hard drive you can get. The days of getting by with 160G hard drives are pretty much over, especially if you are storing lots of pictures with a high megapixel camera. Personally, a 500G hard drive is too small for me right now. But that's just me.
Dual layer DVD burner. This will also burn CDs, but the dual layer units are nearly as cheap as the single layer units are. You can also get blue-ray burners now if you think you'd need that some day. A blue ray disk can store massive amounts of data compared to a regular DVD. And they make CD's look like floppy drives by comparison now.
But, as always, we need to balance our needs and wants with what we can afford. I'd love to have the biggest, baddest processor my mother board is capable of running, but that would cost more than some off the shelf PCs do, so I keep what I have as long as it does the job.
And I looked at Dell and HP in regards to getting XP instead of Vista. Dell seems to offer the most choices, and all I could find on HP's site were 2 laptops with XP, and I don't think they were all that powerful. Dell offers the most freedom there because they give you both so that you can upgrade to Vista when you are ready. And going with Vista isn't as painful as it had been now that the hardware has caught up to the software. Your biggest concern would probably be your printer and scanner if you have one. Make sure they have Vista drivers available for those. Otherwise, you should be OK. Heck, I may even upgrade in a few months.
Good luck and I hope this helps! Sorry for taking so long to answer......