If you want to recreate the Velvia film look (rich deep colours) then use the technique detailed in this tutorial. I find it works really well, but not on all images. It affects the primary red, green, blue mostly, as you can see in the attachment I have included of the cars.
Photoshop Tutorials - Velvia
To set it up to use on a regular basis, edit any photo as instructed and save the settings as a preset called 'velvia', or something similar. Then set up an 'action' in photoshop to add an adjustment layer for channel mixer using the preset you created, but end the recording of the action after the effect has been applied (don't flatten the file in the action). When you run it on any other image it will stop after applying the effect - if you don't like it on that shot cancel, if it looks OK but is too strong you can turn down the opacity from 100% before flattening and saving. You can also set up the action as a keystroke - I use shift/F2 - it's really quick once set up. The process works best where you have a good colour image, but where the colours are a bit flat. This image I posted yesterday used this feature, and you can see how strongly it can bring out the colours in the right image.
Im ready for that spanking now, big boy!!