In reply to blackcat:
Nuts - doubles in mid sizes for harder mixed.
Hexes - I prefer small hexes over equivalent sized nuts in winter.
Cams - 5 for harder mixed - they don't provide a 'get out of jail free' card like they can do on summer rock but I wouldn't like to climb mixed above V without them. Still plenty of times when you can find bomber placements for them.
120 slings - I only carry 1 in summer but take 3 in winter as threads/spikes seem more in abundance.
Pegs - On well travelled mixed I wouldn't bother taking any to be honest, there will most likely be in-situ ones anyway. For a venue like Meagaidh i'd probably take 2 or 3 (knife blades are the only ones i've ever actually placed)
Screws - obviously on ice routes only although I'd take a stubby for late season mixed. 8 is probably enough for most gully style routes, although I took 9 on Poacher's Fall and felt like having 10-12 would have been useful as we belayed off screws on 2 pitches and only had 5 for a 50m pitch.