Here is a list:

"宁可等我搌够钱时再买。"
This is the right strategy.

My list:

1. You need a walk around lens, which should be convenient (large zoom range and not heavy) and inexpensive (so that you can bring it with you for activities like skiing and hiking without fearing damaging it). The choices are: Tamron 18-200mm (~$350-400)or the soon to be available Sigma 18-200mm OS (optical stablization, Sigma's "IS", and my guess is around $500 and available in Jan or Feb).

2. The above walk around lens will not be fast (meaning small aperture), so it would be nice to have a fast lens for low light situations. My choice: Sigma 30mm f/1.4 (~$400).

Now, to pro quality lenses. These lenses will have very high image quality. But the drawback is: heavy and small zoom range.

3. At the wide end, you can choose one of the following:
3A: Canon 17-55mm f/2.8 IS (~$1000) or
3B: Canon 24-70mm f/2.8 (~$1000) or
3C: Tamron 17-50mm f/2.8 ($450) or
3D: Sigma 24-70mm f/2.8 ($400) or
3E: Sigma 18-50mm f/2.8 ($400)

I have the Sigma 24-70mm f/2.8. Choosing 24-70mm f/2.8 has another advantage: they are full frame lenses, so that in the future, if you upgrade to a full frame camera, you can use the same lenses.

4. At the long end, choose one of the following:

4A: Canon 70-200mm f/2.8 or
4B: Canon 70-200mm f/4 or
4C: Canon 70-200mm f/2.8 IS or
4D: Canon 70-200mm f/4 IS or
4E: Sigma 70-200mm f/2.8

I have the Sigma 70-200mm f/2.8.

"用一很旧的镜头：EF 28-80MM/f3.5-5.6（因该属於十年前的产品）。今天拍了几张孩子滑雪照片，效果很糟。"

You should post some sample skiing photos and photos of other subjects taken with this lens. It may not be a lens problem.