the canon stuff is very good but pricey , but that said , if your serious about sticking at it its the same as fishing gear buy the good stuff and do it once .
the camera body is pretty much disposable in the long term (5-10yr) but good glass can last literally a lifetime . With that I mind I bought a few lens that I havent changed when I traded up bodies from 350 -450 and then 60d .
you hear a lot of people talking about fixed or prime 50mm for trophy work but the truth is there are too long on a crop sensor body , great on full frame. it would be better to choose something around the 30mm mark for your camera . I have a 50mm 1;4 on mine and its a great lens but not for trophy shots esp in a tight swim .
mid range zooms or gp walkaround lens are great ,which would include your kit lens @18-55mm , for around a ton secondhand you can pick up an older series 28-105 which is a great lens at a sensible budget , has a little more reach and much better build quality .
longer zooms ...........hmm everybody wants more reach , which can be hideously expensive esp if your wanting to hand hold as opposed to using a tripod . the reason for this is IS or image stabilisation. if you have anything close to a 200mm on the camera it is virtually impossible to hold the thing still enough at full reach , is solves this prob and doubles the price of the lens .......my 70-200 f4 l is rated as one of the best around for image quality cost around 400 quid and is next to usless without a tripod , the IS version of it was £750 and those prices were secondhand .
if your new to the whole dslr thing my top pick would be a good expanded guide , it simplifies all the menus and whether your new to it or not are very worthwhile , I have them for both the dslr and compact .