My full collection:

In this photo:
LEGO cube: This was my first cube, a storebought 3x3. It's also my first (and only) mod!
Rubik's 4x4: This is the official Rubik's 4x4, the Revenge. Fun, but not high in quality. One of the blue centers broke when I tried to disassemble it, but I fixed it with superglue.
Other storebought 3x3: The biggest regret in my collection. Bought this at Cracker Barrel some years ago, absolutely horrid quality even with lubricant. (Yes, said lubricant is vaseline, no, I won't clean it out. Not even worth the effort.)
Rubik's 360: Concept sounded fun, and it was, until it lost its novelty.
Rubik's slide: Fun and simple. Dead on batteries
K'NEX 1x1x2: Several factors led to me making this: I was bored, I never use K'NEX otherwise, and I thought it would be interesting to make a 100% K'NEX puzzle.
Puzzles I wish to add to my collection:
Mf8 Megaminx
A 5x5 cube