Yeah ... you know I was going to reply to this one; I spend about 50% of my time (if not more) traveling back and forth from the US to the UK or the Continent.
While I would have originally recommended the Weekender (aka: Voyage) bag, the problem is that it does not come with a strap (if you see one with a strap - it is a FAKE!!). It has plenty of room to carry both your personal stuff as well as work stuff (file folders, etc.), but if you are burdened down with luggage as well as a Laptop (as I usually am), carrying the Weekender can become problematic (I currently dealing with both a Shoulder injury and now my Elbow!). The Work/Office is also nice, but (in my opinion) really doesn't have enough room to handle both the personal affects and work stuff. So, what does this leave ... aaaaahhhhhh ... my now absolutely FAVORITE B-Bag in the world -- the COURIER (see my thread - CeeJay's Balenciaga bags as I have just posted some pictures of my wonderful Cornflower Blue Courier bag!).
Not only does this bag have PLENTY of room (frankly, more room than the Weekender), but the best part is that there is not only a shoulder strap ... but an adjustable one to boot!! Woo Hoo ... this makes it a HECK of a lot easier to slap on the shoulder -or- messenger style across the chest leaving the hands free to deal with the luggage, extra carry-on stuff or baby carriage, baby, etc.!!! THANK GOD that Balenciaga finally made a travel bag that's a lot more versatile!
When I spoke to Balenciaga-NYC about a week ago, they informed me that there is going to be an even bigger size than the current Courier (holy cow - that is going to be one BMF bag!!).
Another option, is the Messenger style. This is really a Men's bag, so there is no mirror, but there is a long shoulder strap which can be adjusted. It's not as big as the Courier (nor do I believe it comes in as many colors), but for those that don't need (or want) as big a bag, this might also be an option.
While I love the City bag, if I'm traveling, the City (or the Work - I have that as well) is not big enough for me. I HIGHLY RECOMMEND the Courier bag!!