I got these two items for my trip and thought I'd share.
Glasses/Contact 2-in-1 case
Very nice for anyone traveling that wears contacts. A bit bulkier than it looks, but worth it for something that holds all your contact stuff, including mirror for putting contacts in on the train, and that keeps your glasses right there with it.
Toshiaba Gigabeat S
Not really an accessory, but it's certainly handy for one issue that pops up a lot here. This is a great MP3 player that also plays video, but the feature that I wanted to bring up is that you can hook your digital camera up to it and transfer the pictures directly. No more need to bring a laptop, buy extra memory cards, or email them to yourself at a hostel computer. And coming in sizes of 30GB or 60GB, you'll have plenty of room.
Aside from that, it has a few other fancy features (such as hooking it up to a TV for video output). If anyone is in the market for a new MP3 player, check the reviews. Most all of them rave about it and call it the only "iPod Killer" that really rivals it. The link is for the site I bought it from. Cheapest place I've found and while the layout looks kinda shady, the service was wonderful and it has great reviews from resellerratings.com