[Dirk]

for close up's you need a zoom larger than 55 mm. A 55-250 IS could be the lense you're looking for with close up's the detail is fair, for better quality you need a higher priced "L" lense

Alternatively a 17-85 IS is a higher pirced lense and better build and IQ than the standard kitlense. Do not forget that the rebel XTI is a cropped camera so that for all lenses ( EF-S or EF you need to multiply the startting mm times 1.6 and the end mm also times 1.6 so a 18-55 really is a 28.8 mm - 88 mm lense)