Hi Ron,
These are problems well discussed in older threads - I don't know how to put links in - but a quick browse and you'll find them.
The SB80DX (and SB28DX and SB50DX) is the only gun that offers TTL with the D100. In fact it is DTTL and differs from standard TTL. But it does work very well. And I have tonnes of images, now, to prove it!
You cannot fire slaves with the SB80DX. Except possibly another SB80DX? But I have no experience of this. There is a German? invention that does seem to solve this problem (allowing you to slave other guns), but again I have no experience of it. However I have found that as a single strobe with my 28-70, 60 and 105mm lens the SB80DX is excellent.
Subal have just brought out a new housing for the SB80DX, with full controls. Which I have not seen yet.
The SB80DX does not have sufficient coverage for wide angle.
The YS120 and YS90 have sufficient coverage for all lenses wide angle and macro. You can use as many as you want, although you can only wire 2 into the Subal housing. These guns only work on manual - they do not TTL with the D100. And must be connected to the camera with only 2 wires (trigger and ground) rather than all 5. If all 5 are connected the camera will not let you take a picture. Subal shipped my housing with just these 2 wires connected.
Manual flash exposure is very easy to control with a DSLR and offers much more creative control than TTL (or DTTL). I reccomend you use your existing guns with the D100.
I like the SB80DX and use it. But swapping to wide angle (and manual UW strobes) means I have to modify the electronics.
Hope this is of use,
Alex