I don't have anything this year I specifically plan to re-gift, but I've done it in the past. I enjoy giving presents and I'd never give anybody something just to get rid of it or just to avoid buying something--if it's something new that I haven't used and I know they'd like it more than I would, I think it's ok.
My first year of teaching I used our laser printer to print monogrammed notecards for several of my coworkers. The notecards were leftover from the stationary we'd purchased a few years before to print our wedding invitations... on the same printer, now that I think about it! So I guess that was sort of re-gifting, or just using what I already had around the house for a low-cost gift. They were very well received and both ladies and men liked them. Anyway, I gave those out the last day of school before Christmas break. The day we came back, three people stopped by my room and said, "Here's a gift for you, I didn't have it the other day/I couldn't find you the other day/I forgot it the other day" or some kind of excuse like that. It was soooo awkward-- I just wanted to show them I appreciated their welcoming me to my new job and being there for me during my first stressful year of teaching, but they all gave me obviously re-gifted presents as an afterthought, out of obligation. I didn't expect anything in return, and if they had just not given me anything, it would have been fine. Instead it was weird because I felt like my token of appreciation to them had instead become a source of guilt and obligation for them. This whole thing in our society where we don't just give gifts, we have to EXCHANGE them kind of spoils it for me sometimes I guess. Or maybe I'm just overthinking it... I just don't let myself feel obligated to give gifts, I do it because it's fun and if I am not super excited about giving a gift to someone, I don't, and I guess I expect that from other people too but I learned that isn't always the case.
So all that is to say, I don't think it's ok to re-gift just because you feel obligated to give somebody a gift. If you feel obligated, first do a personal attitude check and decide if you are really giving for the right reason. If your reason for giving a gift is something other than you appreciate and care for the recipient, maybe reconsider the necessity of giving a gift.