I've started my first year in industry some months ago in a UK Software company. Since I'm pretty much a newbie I had to ask around for help. There is this guy that has been helping me a lot with work stuff but also with some other stuff not related to work (e.g. I've had some serious issues with my PC and couldn't get it back on track on my own, so he stayed overtime helping me sort it out). Besides that we also get along pretty well and seem to have a lot of subjects in common.
With Christmas coming up shortly I was thinking of feeling Christmassy while also showing my appreciation for his huge support with my PC (being a student, needing a new PC would have been quite a hit to my budget). He is a bit (more?) geeky and I believe around 30yo (although I never thought it was appropriate to ask) and although I like software development I wouldn't categorise myself as geeky. I am not British myself either, so I am not entirely sure how to go about it. I've noticed (Christmas, in this case) cards are fairly popular, so I was thinking of going for that.
I could send him a Christmas card or something else, more personal. But I don't intend to come off as "too friendly" and get misunderstood either.
Also, there are more colleagues around my desk, some that I've never talked to, some that have been nice to me, but not as involved as this one. I am a bit unsure whether it would be all right to give something to one person or seven out of 30+ that are on the same floor.
So, basically, this is my question: Is a card an appropriate and effective approach to show my appreciation? If not, could you advise of a better way?
TL;DR
My goal : show appreciation to helpful and friendly work colleague.
Cultural context: UK, Software Company
Who is involved: Me and another work colleague, both males.
My uncertain approach: Give a (Christmas) card in which I try to convey my gratefulness.
My priorities for the outcome: To manage to convey my appreciation towards the work colleague without coming off as "too friendly" and without being rude to other work colleagues. I am looking for a better approach if a card fails to be the right choice.