If you are coming from a standard digital camera, the kit lens is going to be better than anything you've ever used before. IT's definitely worth having, and the 18-55 range (like a 28-70 in film camera terms) is extremely versatile.
The best quality lens (better image quality than a $2000 70-200 IS L, though far less flexible) is a $70 50/1.8 lens. If you are doing studio photography or wedding portraits, it is the best image quality lens that canon sells. On a Digital Rebel, it is also not very versatile, even though it has great low light capability. THis is because it's the equivalent of a 70mm non zoom lens, which is too long for most normal photography.
The best general purpose lens is the $600 Canon 17-85 IS lens. It's an amazing lens, with image stabilization that can rescue a lot of your shots. Another lens I'd recommend is the 28-135 IS.
But seriously, get the kit lens. Anyone who doesn't think it's good enough is either a serious amateur, a professional, or someone with a lot of money to spend. IT's a good lens to start with and is well worth the $100. Unless, of course, you spring for the 17-85 IS. Then you can skip the kit lens.