I actually like the look of Ultegra 6700, but even I know it wouldn't look that great on titanium bike. Too much silver. Ti looks better with black parts IMHO.

DA 7900 would be a much better choice.

Seriously though, Force works great too. I used to ride Shimano, then rode SRAM Rival for a few months, now I'm going back to Shimano (6700) for the new bike. Neither system is perfect, but they both do what they are designed to do, which is shift gears. It's all preference from there. After comparing all the pros and cons of both systems, I have decided that Shimano works best for me. But that's me, not you.

I'd also consider Rival over Force because they are the exact same thing on the inside. One just looks cooler and costs more. Once you go to Red you will start to see differences in actual shifting performance.