Wow. I can't believe you asked TWO photographers and the answers you got were Sigma's 18-200, and a 70-300 for PORTRAITS and FAST MOVING SUBJECTS. Both of those lenses are terrible for fast moving subjects. Here's the deal. Primes will, undoubtedly, give you the best picture quality. Primes being lenses that cannot zoom. So, if you're going to get a prime, go for anything from Canon, Sigma, Tamron, or Tokina with a focal length of anything over 40mm, and an F/# of anything less than F/3.3. So, any lens from those makers that is at least 50mm, F/2.8 (you'll most likely find a F/1.8 at that aperture) or faster, will be good for portraits AND fast moving subjects. As long as the lens does not say Macro.
If you do want a zoom, don't do get anything that is higher than roughly a 3x zoom. For example, your kit lens is a 3.055x zoom (55/18=3.055). Also, make sure it says F/2.8. Not F/2.8-4.5 or anything like that. F/2.8 ONLY. Follow these rules, and you'll have a lens that will suit your fancy.
These are the ones I'd recommend:
Canon 17-55
Canon 17-40
**Sigma 17-50mm F/2.8 HSM OS** (NOT the 17-70mm.)
Tamron 17-50mm F/2.8 VC
Sigma 50mm F/1.4
Canon 50mm F/1.8
Canon 50mm F/1.4
Canon 85mm F/1.8
Sigma 85mm F/1.4
None of the primes will work wonders for super-wide scenic shots, but the zooms will all work well for those, and portraits. They will be suitable for fast-moving subjects, but the primes will be MUCH more suitable for fast-moving subjects and portraits. Not so much for overall usability or scenic images.
Hope this helped a little.
Mark