WinPooh
Regular
I recommend getting a variety of different puzzles too.
Yes, I like to solve 4x4x4, it is a good relaxation for me. I do it quite slow, in 5-7 min. Small 2x2x2 cube is one of the favorite toys for our 1.5 years old baby
Another puzzle for quiet meditation is octagonal prism. My wife gave it to me recently, and I spent some time before found it's similar to 3x3x3. As to larger cubes, they don't attract me at all for now.
I also have Moldavian pyramid (aka Pyraminx) made in mid 80s, Skewb (don't know exact algorithm yet, it just solves itself from time to time) and Cube-21 (never solved it for more than 10 years).
One day I plan to purchase Mirror-cube because of its craziness and Megaminx because it looks cool