As you can see, the choice of a film is a very personal thing. Your desire for very strong colors would lean toward Velvia, but that film can be tricky to use. I understand that the new Velvia 100 is easier and more predictable than the old Velvia 50 (which Fuji claims should disappear completely by around the end of the year). Kodak Ektachrome G100 is also a possibility. You failed to mention the format you will be shooting. If you are using 35mm, the amateur films are often more colorful than the professional ones. In 35mm you also can use Kodachrome, with its supurb color richness and accuracy.

Coming from black and white, be sure to take into consideration the restricted latitude of color transparency films. Highlights will block up and shadow detail will be lost unless you can control the light (which you can't in landscapes). You lose about a zone at each end. You may want to consider using a color negative film if you do not really need transparencies. These have huge latitudes and still retain excellent color rendition. The Kodak Ultra series of color negative films may be just what you need - high color saturation, excellent accuracy, wide exposure range. You can even have the lab make transparencies from the negatives. For high saturation, the amateur color films negative may also be interesting. They are very high quality, but they don't quite have the look may commercial customers want.