Yes, I think it's acceptable! I own one because I don't want bulky pockets. I was told that it didn't look nice. So there, I got myself a small bag I can sling on my shoulder.
I was in Greenbelt last weekend and BratPack had this exhibit with famous people showing what they carry in a bag. I was inspired to "blog" about it. There are a number of people who use Tumi and I think it's a pretty good brand. My brand of choice is Jack Spade. Yes, it's the sister company Kate Spade. Why Jack Spade? It's simple, sleek, and it serves you well.
Here's what I carry inside my Jack sack!
I have the ff:
2. Business Card holder (yellow)
5. Mints (PocketMist spray and Breathsavers)
Guys, it's ok to carry a bag. Make sure it's manly. Try not to bring a clutch bag. I don't think it's as accepted yet.