I love my cream Coach handbag and have definetly found it to be the most versatile bag I own - no matter what the season. So if you can only own one bag, then DO be persistent and keep looking!
I don't know your price range, but here's my cream coach bag:
http://teamsugar.com/look/1054313
... they do tend to offer a range of cream bags each season. Unfortunately, you can't sort by color on their site. The price may make you choke, but from a cost-per-wear standpoint, I think I'm in the $1 per wear category by this point... by end of '09 it will easily be down in the pennies-per-wear category!
I do not own a single black bag. Okay, that's not true: I have one black bag but I haven't used it in years. I think chocolate is a great color and works well with fall and winter colors. Here are my two chocolate bags, when I get bored and want a change up:
BR bag:
http://teamsugar.com/look/1119521
... a little hard to see in this photo, but I fell in love with the leather. It's sumptious. And it has nifty pockets for cell phone and such.
Inexpensive slouchy bag:
http://teamsugar.com/look/1083943
... which works quite well with mauves and greys too:
http://teamsugar.com/look/1083909
This fall I may invest in one more bag... but I will be looking for something in a fun color. Not sure what just yet, possibly something like this, in purple or the green....
http://www.coach.com/content/p.....ory_id=264
As you can see, I'm a huge fan of Coach - just not any of the ones with the logo prints. I also find BR bags quite nice:
http://www.bananarepublic.com/.....?cid=13920
.... hmmm, some of these soft greys are appealing to me....