I got the 18-55 IS version when I got my 1000D, and for a kit lens at that price, it was pretty impressive imo, and according to many, miles better than the non-IS version.
It all depends on what you are taking photos of and how serious about it, and also budget. For taking general shots when out and about it will be adequate, but you will definitely want to upgrade if you want anything more than that. The f/3.5 you mentioned is only at the 18mm wide end, at the long end of 55mm it is f/5.6 and varies between as you zoom.
I upgraded to the 17-55 f/2.8 IS and it is miles apart in every aspect, but it is more than 10 times the price.........so I suppose it depends on whether you want the best and pay for it, or are content enough with a cheaper more standard lens. There are obviously lenses in between at in between prices which you may be interested in for a fraction of the price. Before I upgraded to the 17-55, I bought the 28-135mm IS for under £200 used and I enjoyed using that as my main walkabout lens for a while, I then sold it on for £160 recently when I no longer needed it.
There are also lenses from other brands like Tamron, e.g. Tamron 17-50 f/2.8 which I've seen people rave about, and is a cheaper alternative to the Canon 17-55, so you definitely have options.
I think the bottom line is, you may as well use the kit lens initially, and then once you play around more, you will have a better idea of what your needs are in a lens and upgrade accordingly. If you sell it, you will probably only get about £60 for it.........