I'm an inexperienced ciderist and I've been researching this very question for around two months.
Many renowned cideries use champagne yeast. The thing to remember here is that champagne yeast is very aggressive and should ferment your must to total dryness (little/no sugar remaining, specific gravity below 1.000) So you may need to back-sweeten to achieve the flavor you prefer.
Check this page out, this guy has tested dozens of combinations of sweeteners & yeasts: http://www.homebrewtalk.com/f32/results-juice-yeast-sugar-experiments-83060/
I am about to do 7 one-gal batches with TreeTop brand unpasteurized cider, with their gravity pumped to 1.065 with white/granulated sugar, and a half-ounce of yeast energizer per gallon added. This is happening in the next 4 days, so keep in touch with me and I'll share my results with the following yeasts:
- Danstar: Nottingham (Type: dry, Purpose: English Ale)
- Safale: S04 (Type: dry, Purpose: English Ale)
- Wyeast: 4776 (Type:liquid, Purpose: Cider)
- Red Star: Pasteur Champagne (Type: dry, Purpose: Champagne)
- Red Star: Côte des Blancs (Type: dry, Purpose: White Wine)
- Red Star: Bourgovin RC212 (Type: dry, Purpose: Red Wine)
- Danstar: Belle Saison (Type: dry, Purpose: Farmhouse Ale/Saison)
The first five on the list I have read multiple positive reviews & successful recipies, the last two are for giggles.
If you wish to read a good book on cider, I recommend: