I have loads of different products for different bits as found none work amazingly well all-round.
For me:
Splitter, fog surround and the bit in the rear bumper: Blackfire Tyre Gel (yes, tyre gel, deal with it!)
Window seals: Collinites 476 wax (yes, wax, deal with it!)
Mirror surrounds: AG Vinyl and Plastic (a bit conventional I know!)
I find the Blackfire gives a nice dark and really durable finish on the fogs and splitter, everything else comes off as soon as it rains, this lasts a bit longer and has a nice dark and slightly wet finish to it, although you can tone it down by buffing it off a bit.
Also got Sonus Trim and Motorkote which works well, although at the moment has been moved to arch duties! Also have Chemical Guys New Look Vinyl but find it doesn't last that long. Now use it for plastics in engine bay and also over the top of Blackfire gel on the tyres in the summer for the uber wet finish we all know and love so dearly!
Have used WD40 in the past too and works well but don't have any right now (or my dad has none left to steal from :approve