What is your photography background? I'm guessing this is your first DSLR. What system are you buying? Canon, Nikon, Sony, etc?
18-55 is a very typical general purpose focal range. For most it would be a good starting point to get used to shooting with a DSLR.
If you came from a point and shoot with a super zoom 10x zoom Len, you may feel like you don't have enough zoom. If this is the case you may want to look at getting a 18-200mm Lens as this will give you a similar amount of range. It will give you a lot of flexibility in a single lens and you won't have to switch lens.
If not, you can get your 18-55 kit lens and a 55-250 or 70-300. This route is slightly more expensive but having lenses with smaller focal ranges typically yields better performance and image quality, i.e. sharper pictures, possibly larger apertures, better color and contrast. This is because lenses with small focal ranges (2-3x) have less to compromise compared to lenses with a larger focal ranges (5-10x).
What type of shooting will you be doing? Landscapes, portraits, sports, etc? If mostly for travel, then a 18-200 may be a good way to go.
If you can give a little background or answer a few of these questions. We can probably help you out a little better.