I can see from the comments so far that there are alot of recommendations for L lenses in the $1000+ range, but the truth is, if you aren't a professional photographer, the difference between Canon's L and their normal series of lenses is probably not something that you want to be spending four times more for.

That being said, your choice of the 50 f/1.4 over the lower cost 50 f/1.8 and preference over the EF-S 18-55 f/3.5 - 5.6 tells me that you have a preference for a fast prime over a slower zoom lens, and that you prefer something with a better build quality. Perusing through your photographs, there is heavy use of the 50, and not so much the 18-55.

Your photographs feel very personal, because the 50 is effectively operating as a 80mm telephoto, but at the same time, you are going to be limited indoors in how far you will be able to step back to get the shot you want.

A wider angle lens, such as a 24mm or a 35mm, or even the EF-S 10-22 will give you the capability of taking shots a little bit closer than you would with the 50.

It is for the sake of flexibility that I recommend a medium-range zoom, something can cover at least the lens range of 24-70. I've been hugely disappointed so far with lenses that have a non-fixed aperture range from 3.5 - 5.6, as I find that at the longer end of the lens, the 5.6 aperture size is too slow.

For Canon, having a criteria of not getting that f/5.6 on a zoom, unfortunately does push you into the L series of lenses or into Tamron lenses.

I do not recommend the 24-105 f/4L IS lens. IS is mostly helpful in situations where steadiness and camera shake is an issue, and will not make a difference in this lens until you enter the 70-105 range. If you are considering the 24-105 f/4L, spend $100 more and buy the 24-70 f/2.8L, which will give you an aperture twice as big for faster speed, better bokeh and good low-light performance.

Telephoto is mainly used for sporting and event photography, where you can't get close to the subject.