Hi Billy, welcome to the Cameralabs forums!
I'm glad you enjoyed the video and found the review useful...
Look out soon for a roundup of general purpose Canon lenses for the 400D / XTi...
If you're after a longer range though, consider the Tamron or Sigma 18-200mm models. Fitted to the 400D / XTi, they'll deliver an equivalent range of 29-320mm.
for a full review of the Tamron against the Sigma 18-200s.
The 28-75mm lens you mention will deliver an effective range of 45-120mm, so won't offer any wide angle coverage.
I'd also recommend waiting a couple of weeks, as there may be some new lens announcements for the Photokina show in Germany.