Although the two answers are correct, I would like to chime in with a slightly different opinion. Note that I am not a professional by any means.
I used to have the two kit lenses for my Sony Alpha 55 (18-55 and 55-200), but 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 from the two zooms to the new one, but I really am much more comfortable with this set-up. I now have a lens that covers a wide focal range to get the work done for small prints, the web, and family snapshots. It lets 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.
When I see something more worthwhile, that I would probably want to enlarge and print, I use the primes, which perform much better than the two kit zooms ever could.
If you'd like a bit of humor on this theme, read John's Shermann take on "18-300 is bad".