I agree with the other INTP's. At the very least it means that I'm really enjoying your company and I really appreciate our friendship and what we have.
It doesn't have to mean more than this, but it very likely could. I usually do this sort of thing as a way of saying, "I'm very, very appreciative of you" or "I welcome you into my inner circle".
Examples:
-someone marries one of my family members
-someone really, really connects with me in a deep and meaningful way and I'd like them to stick around (friends or more)
-I really enjoy you and I'd like to see where things go
Not to ruin the idealism (*beautiful, romantic music record comes to a screeching halt*), but the worst thing you can do is interpret the thoughtful gift to mean, "I've found my forever lover - I'm vowing my love to you until the end of time". Don't put that pressure on him. It definitely means something very, very heartfelt. But, it's more of a "warm, welcoming invitation" to go deeper than it is a "vow of undying love that is hereby unbreakable."
I liked a girl once - was very interested in her. She eventually found out through mutual friends and she called me one night out of the blue and asked me if I wanted to go dancing (like right now!). That's not really my thing - especially for a first date - so we talked on the phone for about 20 minutes and had a nice conversation. I felt like I had let her down a bit by not going dancing, but I was very happy that she had reached out to me and showed interest. During the phone conversation, she had mentioned that her birthday was coming up. She also mentioned that there was this place (2 hours away) that she had always wanted to visit, but nobody had ever wanted to go with her. So, a few days later I called her and said, "I know this is going to sound crazy, but you know that place you've always wanted to go? I'll take you there for your birthday and we'll spend the day there if you'd like - I don't want to put pressure on you as we haven't hung out much before, but if you think you're up for a long drive, we'll go!" She eventually agreed to go and she is still grateful to this day for that birthday gift (we have long since been broken up), but it was my way of saying, "I didn't go dancing with you, but my answer is DEFINITELY yes - I'd like to get to know you better. Yes, yes, yes. Come into my inner circle. Only a few people get in, and I'm officially inviting you in. I have no idea what's going to come of it, but I'd like to find out."