Professional attitude towards business dealings is all one needs.
Bring your best to the table, not wear your best to the table.
Wow Hanz, very impressive and memorable statement. The best I've read for a very long time. Sounds very much like a line which you'll read in books like "How to Win Friends and Influence People". 
If this thread was discussed 5000 years ago, it would probably be "Big axe vs Long Sword vs golden spear...." or something like that. The thing is, the feeling that one needs to wear a power watch or power tie or drive a power car to impress the other side has a historical root. In the past you bring to the negotiation table the longest sword, the sharpest knife, the most bloodied axe, the heaviest club etc to intimidate your opponents. Now fast forward 5,000 years to the present times, the carrying of such weapons to the negotiation table is unfortunately (or fortunately) no longer an acceptable practice (unless you are a member of the underworld) hence ordinary folks who cannot free themselves from the shackle of this practice from deep antiquity resort to wearing and driving what some may consider flashy to intimidate and impress. Now, this is not a criticism made against the TS. Let's be honest, most of us at some point of time resort to this, albeit maybe in another form or to a different degree.
Wow Hanz.. I am impressed too. Very well said. I shall remember to quote it when the right situation arises.
Lol Enkidu... That was so funny. It's like when a bare hands Kung fu master walks into a tavern, nobody would look twice at him (unless he is Wong Fei Hung or Cheung San Feng). But if another Kung fu master walks in with his Golden Broadsword entwined with jewelled dragon and other complications, he makes a grand impression. Or one with a fierce looking Flying Guillotine (makes me think of Tourbillon), the normal folks will be awed (though prob not to another WIS - reads wuxia idiot savant).
So... Like Godzillaz said... A nice recognisable luxury watch probably helps to some extent. After that, it's all up to your real Kung fu. And also depends on how one carries himself during conversations... if one comes across as trying hard to show off the watch, some ppl will be turned off.
But I digress... in my humble opinion, I am in the Rolex camp for TS's quest (although I am a fan of GS). Perhaps the classic Datejust with green markers might suit you? Managed to google one here... Like the 3rd one. Personally, am more of a Rolex sports fan but to each his own.
http://www.watchtime.com/wristwatch-industry-news/watches/rolex-updates-the-classic-datejust/#Do what pleases you... All the best in your business venture and stay around in the forums.
