Welcome to the community, Brooks!
For future references, buying advice is frowned upon here, to say the least! Due to the fact that they're more than often primarily opinion based, and there are a lot of other sites around for exactly that.
I've owned several of these lenses that you line up, so I want to give you my personal opinion.
The 50mm is a great lens, but it's way too narrow for landscapes (my opinion of course). It makes people look just great, and if you're into photographing portraits, it's splendid. But remember, 50mm on a cropped camera will make you back up a bit more often than not.
The 10-18mm, sure it might be a lot of fun, but it's really wide and you will probably feel "out-of-range" more often than not. It's however terrific when shooting targets such as buildings.
EF-S 18-55mm and the 17-50mm are good normal zooms, especially the Sigma one, since it has a constant aperture of 2.8. However, using a zoom as your first lens might be fun and easy, but it won't challenge you as much to become a better photographer as much as a prime might (this is still my personal opinion, some people will argue against this, and they might be right).
The 24mm, as you might expect, is one of my all time favorites, and I used it every day on my cropped camera. The focal range is really good for "all-around-photography". It covers photographing people pretty well, it's fun for landscapes and it makes you move to get to the right point where you want to shoot instead of just zooming in. It's also dirt cheap and light and easy!
You will probably be happy with whichever one you choose, but now you have my two cents about it! Go 24mm Go!