Well I be the first to own up, I am a sucker for buying new figures. With the release of V4, the  G2 females and Apollo Max, I am in overload. The question that occurred to me, are certain figures better suited for certain jobs. I am not asking what figure is best, that I think is a bit subjective. What I am interested in knowing is has one got any views on what figure to use in certain situations ie do certain figure have a particular  features that would suit a particular project
Well I hope that make sense!

You know I was gonna ask the same thing a few days ago but you beat me to it [LOL].
At the moment for me I pick the figure to use to go with the scene, I'll explain a bit more. I have a scene in my head and the type of clothing the character needs for that scene, so then it comes down to which figure I have that clothing item for so at the moment I still use V3 heavily simply because I have loads of stuff for her for most situations.

I can't say the same yet for Sydney, V4, Jessie G2, Miki G2 etc. etc. [LOL].

So that's how I do it!!

Me to. I have the same work flow. So the figure I use comes down to the clothing and props I want to use

the one rule that I use is to not mix figures from different sources, ie If I want a female character in a scene with James I will look to Jessi or Miki (don't have p7 so Syd is not an option) If it's M3 that I'm matching up then it's V3, or SP.  I've found that mixing Daz meshes with CP meshes throws the whole look of the scene off, kind of like using a CG character in a scene with a cell shaded one and trying to make them blend. It's possible with enough work, the right materials/lighting/etc, but unless there is something that is requiring to use those 2 specific characters it's best to change one.

IMO since I still have mostly older stuff being broke and all LOL... V3 is pretty workable with most scenes, I like to use The Girl for the gritty/dirty/exciting scenes because she just has the right look for it. As for anime, I stick with Aiko over Maya Doll only because I think she has much more potential.

Granted these are 'my preferences' and they aren't written in stone. Alot of times I may try out a few different figures in a certain scene before making a final decision. It helps to see how the lighting plays on the features you want to focus on especially since there are so many different morphs out there and its lots of fun to see how different each model will look when its done!

So my suggestion is, just try out all of them since you said you have most (or all LOL) of them. With environment it is important to have just the right person in it but remember, you're the artist so you get to personalize it! :D