The best Canon  digital SLRs for travel are Canon Rebel T1i or EOS 500D or Canon Rebel XSi or 450D.  Both DSLRs are light with great image quality.  The new Canon T1i or 500D with HD video mode can be used to capture some stunning videos when you travel.  May be the most important is to select the right lenses when travel: It all depends on where you go.  If you visit cities, museums, or aquariums, standard lenses with low light capabilities will be needed, the best one is Canon EF-S 17-55mm f/2.8 IS USM.  I found that this lens is even better  than Canon EF 50mm f/1.4 sometimes for low light photography you shoot moving objects at low light.  The three stop image stabilization  works very well.  The focus of this lens is fast and accurate, which is better than Canon 50mm f/1.4 in this regard.

A telephoto lens is also very useful when travel.  When I took photos in New York City, I found the most interesting photos I took are those taken with Canon 70-200mm f/4L.  The recent released IS version, Canon 70-200mm f/4L IS USM is an ideal telephoto lens for travel.  This lens is only about half of the weight of Canon 70-200mm f/2.8IS USM and it is very sharp.

If you visit national parks, you might want to carry a wide angle lens such as Canon 10-22mm.  For shooting wild life it is good to take long telephoto lenses such as Canon 100-400mm.

A light tripod is also great to carry for travel photography.  Without tripod, it is impossible to take photos with long exposures.

Canon has instant rebates on Canon XSi and Canon 17-55mm, Canon 10-22mm, Canon 100-400mm and Canon 70-200mm f/4L IS USM.