I think u have to be more specific, for a newbie, the ef-s 18-55mm is good enough.. the question is wat type of photography u wan to go into fr eg. macros, or u wan take photos of wildlife n nid a telephoto... N give us a budget cos some will recommend expensive lens... hahahaha... imho... heehee..
Do you upgrade for the sake of upgrading? As if the kit lens is limiting u in one sense or the another?.. or do u need that extra reach? or u need sth better for low light shooting blah blah blah. You need to be specific on what do u like to shoot mostly? For us to aid u further dude
of course, 18-55 is limited as your focal length is limited. But again, like what the other brothers are saying, it depends on what you want to zoom into. Some people, 135mm is fine, but others will say they need 600mm for birds. It depends on what is your particular subject.
Also, it depends on how deep is your pocket. It is still alright to be walking around with a 400mm L lens, whether silly or not is a personal issue, but question is can you carry it around all day long?
If you are not sure, you can try getting a 2nd hand 55-250 in B&S section so that you can still keep your 18-55.