Common question: What are the best skis for freestyle skiing? Answer: Depends on what type of freestyle skiing you do. Typically, the question is about skis best suited for the terrain park. Skiers all have their own unique style, just like everyone else. So, certain skis may be better suited for your style. There are many quality park skis, so I can't recommend a particular manufacturer. That said, here are a few things to consider:
Twin tips: Having tips on both ends of the ski is not a requirement, but it is helpful when learning how to ski and land jumps backwards. You can ski and land switch without twin tips, but if you're going to be buying skis, get some twins.
Width: Width refers to how wide the ski is underfoot; the most narrow part of the ski. I would go with mid to upper 80 cm's. This gives enough width to float you in powder, but isn't too wide for tricks and features in the park.
Length: Length can be personal preference. If you are new to the park and just learning tricks, short is better. Riders talk about "swing weight" on park skis. Short ski's are easier to "swing" onto boxes and rails. (as are more narrow skis) General guide: Stand the skis up next to you. The tip should be somewhere between your shoulder and the top of your head.
Bases: A dedicated park ski will have reinforced bases to protect them from hard features like rails and boxes. Any time you session a hard feature, you will cause damage to your skis. These bases will help the ski last longer when put through this abuse.
Binding Mounting: True park skis have bindings mounted in the middle of ski. (center mounted) This allow one to ride forward or backwards (switch) easily. Conventional skis are mounted more towards to tail of the ski. If you plan to ride all over the mountain, but occasionally take a lap through the park, a conventional mounting is recommended.
Graphics: If you like everything about the ski but hate the graphics, get some stickers...