I know I've left it a little late, but I thought I'd pass on my advice regarding gifts for knitters. As an avid knitter myself, experience tells me that most non-knitters shy away from purchasing knitting-based gifts for one or both of the following reasons: a) they don't know what to purchase or; b) they're worried they'll buy the wrong thing.
Now, I really believe that in some cases it's pretty easy for a non-knitter to buy a great gift for their knitting friend or partner. As when you buy other gifts, choosing something they'll like can come down to paying attention to the individual or their possessions. It's worth keeping an eye on your knitter throughout the year, so you can get an idea of what sorts of colours they like as well as what sort of things they like to make. Additionally, when they make a comment about something they like connected to knitting, it's worth taking a note down of what they've said. (This goes for all occasions, not just Christmas. If you keep track, you need never wonder about knitterly gifts again.) One other thing: if you're thinking of buying yarn, please make sure you check what yarn brands/types they use most regularly. If required, please snaffle a label or two (we usually lose them anyway).
Of course, I'm aware that most people (read: men in particular) don't have the foresight to plan gifts appropriately and this extends WAY beyond knitting. This is why I've put a guides together, of general things I believe most knitters would appreciate for Christmas. Of course, please don't take my word as gospel on this and, for the love of god, please make sure you check that they haven't already got some of the things included. Do note, however, that for most of us, regardless of how much yarn we already have, we won't be disappointed with more so long as it is the kind we like. Equally, some things you can never have enough of. For example: needles, and in my case, sock yarn.
Addi Click Interchangeable Needles Set: £86.75 | Lanolips Lovely Lanolin™ Intense Hand Balm: £9.18 | Johnston's of Elgin Cashmere Knitting Yarn: £19.95 per 50g | Clover Steel Amour Crochet Hooks: £93.77 | Pony Knitting Needle Point Protectors: £0.75 | Cath Kidston Woodland Rose Craft Bag: £26.00 | Regia Fluormania Color Sock Yarn: £7.99 | Cath Kidston Little Leaves Tape Measure: £5.00