I'm a big advocate of hard sided luggage because on a trip to Puerto Rico to visit my cousin I had a soft sided bag and a fellow passenger thought it was a great idea to being back a bottle of olive oil improperly stowed and yep, you guessed it... Not only were my clothes destroyed (the entire top 3 layers) but also my treasures I brought back. Soft sided luggage has its benefits though because you can generally cram more in and they usually have very useful front pockets. The key with either hard or soft sided is choosing the lightest bag that you can afford. Look for one with internal separators and most importantly 4 spinning wheels. When I see an inexperienced traveling fighting their two wheeled suitcase while they run to catch their plane I am always grateful that I chose one that's easy to maneuver. I purchased my current set on Amazon.com for $140 for 3 sizes! I also love this one by Lulu Guinness and then there's this amazing soft sided bag by flight001.
Tip: Pack without using the extender zipper so you'll have room to bring back your treasures without going over the weight limit.