If you plan to wear the fleece as an outer layer, I would recommend windstopper for sure. Even on a mild day, skiing at a fair speed will send a chilly breeze through regular fleece products, and you may as well not even be wearing them. For an inner layer, I would go with a regular fleece -- it will breathe better and be more comfortable.
I have the Mtn Hardware Mtn Tech jacket with the windstopper fleece, which is my outer layer on mild days (anything above 35F when it's sunny out and no rain/snow). It has decent breathability, feels like a shirt rather than a jacket, and keeps wind/breeze out at speed. I tend to wear it over a single light base layer. It's a very nice jacket, and well worth the cost.
On cooler days, or when it's raining/snowing, I wear a goretex shell as the outer later. If it's really cold, I have a super-thin fleece zip-T sweater from LL Bean that I wear underneath. It has a waffle-pattern fleece fabric. I like it because it's not bulky. I am pretty sure the Mtn Hardware Mtn Tech jacket would be uncomfortable as an inner layer under a shell. It's not as soft or floppy as a regular fleece, and of course, the windstopper would be overkill and hamper breathability. For an inner layer, any old cheap fleece ought to do -- I doubt it matters. I would shop for one with the proper weight and fit. To me, the thinner and lighter the better.