This is a very general question. There are no best cameras or best lenses, it depends on your needs and uses. Many people, as travelers, would put size as one of their primary concerns and are plenty happy with a good point and shoot or hybrid. Others want SLR. As technology evolves, the gap between the two is closing.
SLRs offer interchangeable lenses, so you can get the best lens for a situation. They also offer superior autofocus systems that are capable of tracking moving subjects. They also allow rapid firing of photos, though this attribute is now often found on higher end point and shoots – heh, and iPhones.
There’s no question that SLRs can offer more professional results (in situations), but people misinterpret that to mean that they are uncompromisingly better for all situations. If you’re taking pictures of landscapes in decent light, the SLR offers very little advantage. In fact, if your subject isn’t moving the difference isn’t great with these exceptions: low light (SLR is always better), portrait photography (though if the point and shoot allows external lighting you could do just fine). There’s other specialty types of photography, such as macro, where an SLR excels because you can get special equipment for that niche. And for fast moving subjects (e.g. Sports), there’s no question that SLRs dominate the competition.
But people get SLRs expecting that it will simply make their photography better. Then they go out and shoot landscapes or something and wonder why the results aren’t any better than their point and shoot – or even worse than their friends point and shoot, who actually knows how to use his camera. People also get SLRs and then want one super lens because they don’t want to deal witch changing lenses all the time. You’re giving up one of the fundamental advantages of an SLR. If you’re going to do that you might as well get a hybrid.
So long story short, it depends. If you do decide that you want an SLR, and you want Canon, then yes, the Rebel is a fine camera to learn about SLRs. With good glass it can produce images just as good as the really expensive cameras. As to which lens, start with the kit lens(es), learn how to use the camera, then grow from there.
