Pictures speak louder than words... so I thought I'd post some examples of slides. I love slides!
These are all unprocessed straight out of the scanner, only resized. So they are only as good as my settings while scanning, but should be somewhat consistent. Usually you would want to do a little PP to get the most out of the slide.
Sensia and Velvia are the two I use most. Sensia is a good value film, but when you want vivid colours try Velvia.
Notice how Sensia is quite neutral in colour and generally pleasing to look at.
Fuji Sensia 100 Fuji Sensia 100
This is the Portrait on Velvia example, sea and sky look very nice though.
Fuji Velvia 100F
You can get some deep colours out of Velvia. I like the results of blue and purple especially.
Fuji Velvia 50
Hope you can see the pictures, if not, tell me and I'll fix it.