I agree with a lot of the advice above. Sierra Trading Post is great but hit or miss in terms of sizes and styles.
For hiking boots, if you don't have any prior experience with them, you absolutely want to go somewhere like EMS or REI first and spend some time with a salesperson who knows what s/he is doing (in CT, Trailblazer and Denali are excellent stores for knowledgeable sales staff), because you want to make sure you know what to look for in the fit and how your particular foot characteristics will affect the sizing of a particular brand and style. Once you settle on a size and style, if you want to shop for the cheapest price it's easy enough to search the web for the best deal on them.
The best pair I ever had were a style of Vasque that they no longer make, and I haven't found their more recent lasts to be a good fit for my foot. Similar experience with Asolo. Used to love Hi Tecs but not sure about their quality anymore. If you are doing semi-serious hiking you want all leather or some combination of leather and Gore-Tex. And a Vibram sole. Definitely a Vibram sole. Merrells are generally a more comfortable but less precise fit in my experience. LL Bean is always worth a look, too, especially with their generous return policy.
If you want winter boots that aren't necessarily hiking boots, look no further than the Keen Anchorage or Anchorage II (depending on whether you want insulated or not). They are pull-on boots, which makes the on-and-off soooo much easier when you are running around a lot. I think I wore them for almost three months straight last winter, including to work most days, and only took them off to put on my ski boots (and the Keens are great for wearing to the ski mountain, again for the easy-on, easy-off). I got the un-insulated ones because my feet run warm and I would rather add a pair of heavier wool socks when needed than risk being too hot.