@snood,
One viewpoint is to buy the most powerful machine your budget allows, because what may seem like overkill now will not seem so later on.
Another viewpoint is to buy the machine that fits your more immediate software needs only, and then upgrade parts or replace entire machine later on.
Another viewpoint is that most new machines do pretty good with most applications most of the time, so unless you're running high end audio, video, multi-tasking, gaming, etc pretty much any new machine will be OK.
I figure buy what you like and have fun!