My boyfriend's been doing that lately, too. While talking about our friend's engagement ring and how she wanted some extra diamonds on it, he joked, "Well you're getting whatever I pick out!" Also, while discussing the groom's ring and how he wasn't getting platinum, my bf said to me, "I want platinum."
And while looking at pictures of that same friend's wedding (the couple cutting their cake), he said, "I'm going to use a samurai sword to cut our cake."
It's nice when they say things like that. Girls always get a reputation of getting so caught up with engagements, so it's nice to see that while they're usually quiet about it, the guys are thinking about it, too.
So good luck to you with that! Hopefully he'll be popping the question soon!