Which is best from these to cameras?

I want a camera that has the best shutter speed and I wanted to know which is best from these two cameras; The Canon 550D( with a 15-88mm lens) or the Nikon D3100( with a 55-200mm lens)

Of the 2 listed, the Nikon has a better lens configuration that the Canon. I believe the Canon is a better camera overall.

Both go from 30 seconds to 1/4000.So, no difference.

I strongly suspect you have no real idea what shutter speed means.

What do you mean by the best shutter speed?

Fastest?

Fastest at a certain ISO?

Slowest?

Most Accurate?

Least Delay?

Nikon & Canon are more or less equal in the camera world. They have the same available shutter speeds. I'd go with the Nikon myself.

When you're comparing dslr cameras from Canon and Nikon there's no "better", there's different but not better. Both companies make high technical quality with lots of attention to detail. Both cameras will last your for many years if you take proper care of them.

The major difference, as I see it, are two things. One do you know how to operate such a camera?
Do you know what various (unique) lighting situations will effect your photos and what settings you can make to get the best results? What do you know about lenses?

If the 15-88 is the only lens you'll get with the 550D I'd recommend it because I own Canon and I know their quality level is extremely high for one and two the 15-88 is an excellent size for a general lens. That's especially true if the 55-200 is the only lens you'll get with the 3100.

Nikon D3100 is great, not only for you, but also for your non-photographer spouse; my XSi took phenomenal shots, but I had to know how to set it. Can you imagine me going to my non-photographer wife and say, "okay, when you take indoor shots of our kids, set the camera on A mode (Canons expose for ambient light in A mode and adjust flash for fill, that's great), +0.7 exposure compensation, ISO 400 or 800, white balance on cloudy, and shoot." My wife was lost at "okay." Sure the custom modes on the 40D would have helped, but the 40D is old technology; can it take 1080p video? I didn't think so. Plus, what lens are you going to use with the 40D? The 17-55 IS? Great lens, but who wants to spend $1, 000 for a non-weather sealed 17-55 dust collector (google Canon 17-55 and dust)? Will 17-55 be enough for your telephoto shots? Your kids' baseball games? Didn't think so. What about the Canon 18-200? Sub-par quality, noisy, overpriced.