I used a rucksack for my WHV, it was easier to carry around and grab from coaches, trains etc. Go for one that spreads the weight evenly and feels comfortable for you (ie. that you're not going to topple over!). It can be a pain having to empty it if the item you want is right at the bottom but other than that, it is much easier than lugging a suitcase around (and it's also more comfy to sit on / lean against if you have long waits anywhere :wink:)