Although the two answers are correct, I would like to chime in with a slight different opinion --- notice that I am not a professional by any means.
I used to have the to kit lenses for my Sony Alpha 55 (18-55 and 55-200) and switched to a new configuration where I have a 18-250 and a couple of nice, sharp primes (a 35/1.8 and a 105/3.2 macro).
I have probably lost a bit of sharpness by switching the two zooms with the new one, but I really am much more comfortable with this set-up. I have a lens that cover a lot of focal range and get the work done for small prints, the web and for the family snapshots. It let me switch from a moderate wide angle to a nice zoom --- got that squirrel stealing a nut to my daughter while I was photographing the view of a lake.
And when I see something more worth a good photo, that I probably would want to print and enlarge, I use the primes, that are much better to what the two kit zoom could ever delivery.
If you like a bit of humor about this theme, read John's Shermann take on "18-300 is bad".