No idea what P & S is, sorry. Thinking of having the option to put on different lenses. Yes, fast actuation so the photo takes the shot as you depress the button, rather than a second or so lag time.
Which model in Nikon etc?
I was just looking at used Canons for someone and found the 30D going for about $200-$250 and the XT going for $125. They're still decent cameras and without a budget it's hard to actually recommend anything. A 7D would be a great camera but used they're about $1,000. Now on to lenses, Wildlife usually requires magnification. You can get 70-300 variable aperture lenses for about $300 or so, but the quality in those are going to be kind of mediocre when compared to a single aperture zoom like a 70-200. The problem there is that Canon's cheapest 70-200 is about $600 with the newest version going for $2,400 IIRC. That's the 70-200 f/2.8L IS MkII. Nikon only has one 70-200 and it's the expensive one. You could go with a telephoto prime, but even those are expensive. Teleconverters will help, but again you lose quality and they'll not work with every lens.
So, what's your budget and what's your expectation of quality. You may be happy with a 70-300 variable aperture zoom, but there are people out there that can't settle for anything but the best.