canon 15mm f2.8 fisheye, very sharp and reasonably wide on a crop body.
canon 24-70 f2.8L, great all around lens, weather resistant, very sharp, and reasonably inexpensive if you find it used.
zeiss 50mm f1.4, no explination needed. especially for video.
canon 70-200 f/whatever you can afford, mandatory in any serious collection.