Hi Wellow ...
I have quite a few Balenciaga Bags (Voyage, City Classique, Office/Work, etc.) in a variety of colors.
First of all, if you want the absolute - definitive "guide" to authentic Balenciaga Bags, the person to get it from is Dudeilove you (I believe she still has them up on eBay). This gal REALLY knows her stuff and her guide shows the difference between the real ones and the fake ones. This will prevent you from buying a fake one on eBay if you were ever considering it.
Now, as far as the colors go - the Burgundy is a superb color (it really looks like a beautiful glass of Burgundy Wine!). I also think that it goes with a lot (looks great with Jeans but also work clothes). I also have the Rouge 2005 City Classique. Now, mind you ... I LOVE
the color RED!!!! I wear it like most folks would wear Black or Navy.
I am not a fan of the Lilac color. First of all, the lighter colors will pick up the dirt a LOT faster. Secondly, it's somewhat limiting (as far as putting it together with other clothes). More importantly, I believe it was a 2004 color ... so, I'm not even sure that you can get one now.
At the present time, Balenciaga has the Holiday "Pony Hair" collection out (you've probably seen tons of them on eBay). I can't say that they rock my boat, but some folks seem to like them.
Personally, I would probably go with the Burgundy because I really think that it's the most versatile.
BTW ... just to let you know ... it seems as though Balenciaga is using a different leather than past seasons. The leather on my Red bag is not as nice as my older bags (especially my first - the Black Voyage). I've talked to a bunch of other B-Bag "addicts", and we all say the same thing. I hope that Balenciaga goes back to the original leather manufacturer!