Geoff;
I shoot a lot of trans. films, and I concurr with the previous poster, that they are all fine films, but here are a few of my choices. I love Fuji Velvia for the rich colours, and for some things in particular, like landscapes, nature and anything with bright punchy colours that you want to emphasize, but for some other subjects (and harsh light!) its' too much over the top. Then there is either the Fuji Provia 100, which is a bit less contrast and saturation, and the 400X is a good choice for higher speed, a bit more grain than the other two, but the colours are still good. There is Kodak's E200, which I don't like as much as the 400X, my opinion only, as there are some that like it a lot. Also, Kodak's E100S (saturated) and E100VS(very saturated) are a good choices if you're shooting 100 speed. Different from Fuji's offerings, but nice also. I used to shoot a lot of the Kodak (there also used to be a E100, that was less saturation than the "S", but I haven't seen it recently), but lately have "defected" back to Fuji.
You may want to try a slight warming filter if you are shooting in overcast conditions, as you may find the results a bit on the cold side otherwise.
My personal opinions only.
Go and shoot some, and enjoy!
Keith