What Brad said (except I haven't much experience with kodak's newer films, G and GX)
Provia produces stunning tranies that are bit truer and less contrasty than Velvia.
The e100 (my references are a bit out of date S, SW and VS) films by kodak are bit more true (at least with S now G) than Provia and (especially in the case of SW now GX) warmer and capture better shadow detail. Kodak VS is somewhat similar to Velvia, but is much better on longer exposures.
Oddly, I really like older kodak tranies EPN and EPP for big tranies. Both films are pretty much spot on in colour and contrast and offer the best shadow detail. They suffer from larger grain (who cares at 2 1/4 or larger) and tend to buck the current trends.
Fuji Astia is very similar to EPP.
In 2 1/4 e200 is the sleeper film. It is very pushable (as well as pullable) the extra stop and push option allows for greater opportunity to filter and and makes for an extremely easy film to use. The images it produces, belie the speed.