This Vader mask I bought for one reason. The lenses are warped enough that they're pretty close to my prescription lenses. It makes this one of the few masks I can wear without my glasses and still be able to see.
Removable helmet Vader was purchased in the late 90's. I had 3 eras of toy collecting. Childhood, the late 90's, and today. This was one of the ones I sought out, picking it up for way too much at a comic book convention. At the time I loved this toy, and it's adorable pasty white Anakin Skywalker. Also, removable hand. Of course that was before I really began to value articulation. The old Star Wars toys are pretty bad about that.
This vader was a gift from Mario when I started to get back into 3.75" scale figures. Although the articulation still isn't as great as I'd like, with cut joint elbows, but it was free, so can't beat that.
Galactic Heroes keychain: it's pretty much a Galactic Heroes vader with a keychain attached to it. It was a gift from my mother who picked it up from a sale. My mother knows I like "sci-fi stuff" so sometimes if she finds something on clearance she thinks I'll like she'll pick it up. It's usually hit or miss whether I do like it, but sometimes it's a pleasant surprise.