This link might help you out.
http://www.clematis.hull.ac.uk/index.cfm

I have 'Polish Spirit' and it has been a prolific bloomer from day one. I also have a Nellie Moser but it has never bloomed for me. I started a couple of the yellow ones (sorry I can't remember what it's called) from seed and they have been great bloomers too. I am in Manitoba, Zone 2b.

another one would be Ville de Lyon. Nellie Moser, Sorry yours didn't flower for you brokenhead, I had one, it was very pretty, and full. Lost it because of some renovation.

I planted Niobe this spring (for the second time - the first died of unknown causes two years ago), and I would like to add Alpina "Tage Lindell" and Nelly Moser next year. I had a three-year-old Comtesse de Bouchaud that died while we were out of town for two weeks (I forgot to have our housesitter water the plants). I have the obligatory jackmanii, that loves it's spot so much it needs a larger trellis.

Meagan

Thumbs up for jackmanii and the similar Jackmanii superba. I also have a smaller size one called Hagley hybrid with big pinkish blossoms. It fills a 4 foot trellis rather nicely and grows in part shade.

Also trying one called Victoria but it sort of resembles Jackmanii but with less petals and perhaps a bit more blue-purple.

As a precaution, I usually mulch peat moss or leaves over the base of the clematis for winter and then ensure I pile lots of snow cover.

I have tangutica but don't find it that invasive, though to be honest it's in a poor soil spot by the carport that doesn't get much watering, fertilizer, etc.

glen