Need a recommendation for lens

Recently purchased a 40D body. Have been using a XSI with the 18-55mm kits lens. What would be a good, inexpensive (not L) lens for all around shooting to replace the kits lens? I do mostly family style shooting, but also do landscape and trying to learn portrait shooting with the grandkids. I also have the 55-250mm and the 50mm 1.8 II in my bag.

The 50 is a pretty good length for family shots. I generally do those with a Tamron 28-75. However, if 50 is the shortest you have, you probably need something shorter to round out your kit. I have the EF-S 15-85, which is a very nice outdoor walk-around lens on that camera, but it is rather slow for portraits and candids. If I were buying something faster in the shorter end of that range, I would probably get the Tamron 17-50 non-VC, which is very sharp and quite inexpensive. Personally, I don't find vibration control (image stabilization) much of an issue for the work I do at those focal lengths.

To stay on the safe side of the budget I would recommend 35mm f/2 from Canon. But I really do not know if this suits your portrait style. Or if you have more money and you want to be more on the portrait side you can go with 85mm f/1.8 .
If you prefer zooms paddler4 mentioned a very good zoom 28-75.
Cheers,
Nic

50 1.8 is inexpensive and capable of producing very good images.

If you are shooting landscapes then you can consider inexpensive manual focus prime lenses. Nikkors work quite well adapted to an EOS body. They can also work well for portraits - but will not work for faster moving small kids.

For portraits, I like the Nikkor 105 2.5 AI or AIS lens - this lens has pleasing bokeh and is sharp - one of Nikon's so called legendary lenses. It runs about $100 used.

If you're trying to replace the kit lens, you'd probably want to look at one of the 17-xx lenses from Sigma or Tamron (the Canon 17-55 is said to be an excellent lens, but doesn't meet the "inexpensive" criteria - it's up in the 'L' price range). Tamron 17-50, Sigma 17-50/17-70 OS are well-regarded lenses. If you go to a 24-[I]xx or 28-xx lens you're going to lose a significant amount of FL on the wide end, which will limit you in close quarters/indoors.

I haven't shot any of the 17-50 variants, but am very fond of the Sigma 17-70 OS. It's a sharp lens which focuses quickly and the focal range is very useful on a crop camera.

Now that I have read the answers and think about it, I am really looking for a walk around lens to replace the 18-55mm kit lens.