I vote for the tan.
I bought the red/burgundy distressed/snakeskin ramona back in January and returned it.
Although the red/burgundy was a rich color, I found that it had too much of a pink undertone and I just didn't love the color as much once I tried it on with different outfits. Here is my previous thread, which also contains pictures I took of the red/burgundy:
http://forum.purseblog.com/handbags-and-purses/jimmy-choo-burgundy-ramona-s-s-07-a-83899.html
In the end, I loved the color of the tan so much more, and that is the one color I would have chosen if I didn't already have a similar colored tan bag. The tan is a great year-round color, the snakeskin detailing really stands out on it, and it is easy to match.
Can't wait to hear about which one you decide to get!