business attire in vegas?

I wouldn't wear the sneaker to dinner or club (unless they are very stylish and even then it's iffy)
It also depends on the jeans. My boyfriend usaully wore them out and even in Vegas was fine. Now these are stylish jeans like Diesel or Armani and such....no Wranglers ; )
He also wore alot of button down dress shirts untucked and sleeves rolled up but with some nice 'blingy' cuff links
A few times for dinner he did go with the 'stylishly casual' suit & tie bit.
In Vegas (as is other cities but more so in Vegas) stylish attire rules. As does little details such as nice (clean) shoes (hey just get yourself a pair of Aldo loafers they aren't that expensive but look nice with jeans na dress slacks)
Nice jewelry works well too. Just look put together and a suit shouldn't be necs ; )

Clubs require very stylist dress and a few restaurant require business attitude but the shows, gaming areas, buffets and other eateries usually will take you as you come expect NO flipflops and tank tops. Sneakers and jeans with a button down would be very acceptible. How you dress is NO indication of your weather in Vegas, in fact, many whales (super high betters) wear jeans.

Nice restaurants and nightclubs are generally the only places with a dress-code.. Slacks, a button shirt and black-soled shoes will get you in about anywhere without any problems... Some of the really nice restaurants prefer you wear a jacket.

all dives will accept that style of dress
Strip will not. Suit not necessary but good slacks, dress shoes, and decent polo with collar should get you in to major clubs.. To increase you chances wear a sport coat[summer weight]
Casino wear what you describe above--clubs wear what I describe.