Depends how many lenses, what kind of photography you figure you'll be doing. Mine's a Lowepro Rezo 170 AW, fits a few filters, the D50 with a smallish lens mounted (50mm), a secondary slightly larger lens (currently the 18-55 kit lens), the battery, charger, some other misc stuff (with a bit of wiggling, anyways). I'm not sure if the 70-200mm will fit in there properly, I haven't seen the dimensions first-hand, but I think it will (11.65cm length from mount to tip, according to the site)
If you're taking more, then upgrade. My Lowepro cost about $45 CAN I think.
My Crumpler 5 Million Dollar Home suits my D50, 18-55 and 70-300 lenses plus wallets, mobile phone and other stuff just nicely (with room for one more lens or a flash). Of course you can go bigger or smaller if you want.
After recently upgrading my bag, I'm going to urge you to buy a bag that is big enough for you to grow into. I bought my first bag thinking it would be the perfect size. Now, a SB600 and Nikon 80-200 later, I was forced to upgrade to a bigger bag.
I'd rather have extra space and know I could load everything I will eventually own.
I subscribe to the lighter is better theory. After years of lugging Notebook computers through Airports the last thing I want to do is carry all my photographic gear all the time in the off chance that I may need some obscue filter or one of several lenses. I'd rather have a smaller bag that has room for a body and a couple of lenses and or a flash and enjoy my days activities rather than be weighed down like a pack horse. Also one very important thing to consider. If you have ALL your gear in one bag ALL your gear can be lost / stolen / destroyed INSTANTLY.
I went for the Orion II Trekker and it does just what I need, holds D50 with 18-55 on board, 70-300, flash and random stuff(MP3 player etc). As some of the other posters say, depends what you need it for.
Incidentally, it doesn't look like a typical camera bag which may be better for security when travelling. Plenty of room for snacks and so on too.
hope this helps take a look at a singer bag from addorama my wife and I first saw one in canada hikeing so I picked one up-- cheap and worked like a charm you can walk for miles and not worry about climbing or bending over have a look ----j
If I had to go with a camera bag, id probably go with Tamrac. Most if not all their products are made in California, and of quite high quality. On top of that, they have what seems like a bag for every different combination of gear, so finding one that fits just right shouldn't be a problem. I think the explorer series is nice for storing one body plus an extra lens.
However, depending on what parts of Europe you are travelling through, you may not want to carry your camera in a bag that looks like a camera bag (i.e. thief magnet). In that situation, I would prefer to pack the camera in a form-fit case (i.e. the Nikon semi-soft or anything with that shape) and then toss that into a regular backpack. Alternately, you could wrap the camera in a T-shirt and put it straight in.