Desktop: one of the new i3 iMacs will give you a few years good service. Just pick the screen size you want. I would not go w/ the mini. It's a sucker trap as a regular computer. C2D is on the way out and Apple routinely designs software for its fastest machines, not slowest. It doesn't have "staying power" and went coupled w/ a monitor, keyboard, mouse cost just as much as a low end i3 iMac.
Laptop: 15" i5 MacBook Pro. Pro is more than you need, but the MacBooks still have the C2D chips, which are fine for today, but likely to be inadequate sooner than you'd like as software is written for faster machines.
Of course if you are a serial upgrader and never keep a machine more than a year or so then a MB or mini is fine. Those computers are great, but do not offer best "bang for the buck" due to the long-in-the-tooth position of the C2D chip.
Another alternative if you are really a light user is an iPad.