Hi there....I wanted to ask about which lens should I buy again......?

The Nikon 18-200mm makes some compromises in quality to get that lovely zoom range, but it's still pretty good. Unfortunately the third party brands don't do 18-200mm as well, and the Canon brand 18-200mm isn't as good either. For telephoto, Canon makes a very good 70-300mm IS. They also make a cheap 75-300mm that isn't as good. Tamron makes a cheap 70-300mm and a very good 70-300mm VC that is reputed to be competitive with Canon and Nikon brand's higher end 70-300mm models. For the wide to slight telephoto end, if you have the money it could be worthwhile investing in the Canon 15-85mm IS. If you someday upgrade from the 1000D to one of Canon's 18MP models, you are money ahead by having lenses that can match that kind of resolution.