I commute all year and have tested out a fair amount of kit before settling on my current set up so hopefully this helps....
For scarfs, I use Buffs - there are various different types available but I use the original ones most of the time but if it's really cold, I also have one that has a fleece bit at one end. Buffs are a bit more expensive than the alternatives but I've found that they keep their elasticity longer so work out to be more cost effective in the long term.
Glove-wise, I have some Alpinestars Arctic Drystar gloves which are pretty much a short cuff version of the Apex ones IIRC. They're OK but not the best once the temperature drops into mid single digits and below. However, they work really well with heated grips as they allow the heat through and trap it pretty well once it's there. I also have a 2nd pair which are my go-to winter trail riding gloves.
When I don't have heated grips available or it's really cold, I have some Alpinestars WR-3 Gore-Tex gloves which are much better in cold temperatures than the Arctics but are thicker so restrict feel a bit more but not too badly. If you don't have heated grips, then I'd definitely recommend them (just did a quick Google of them and Sportsbikshop.co.uk are doing a bit of a discount on them at the moment).
However, if you're not fashion conscious, bar muffs are the best option for winter riding IMHO - especially with heated grips.... mmmm, toasty!