Depends on what you are looking for. If you want the full on, over the top Vegas type, then there have been a lot of good recommendations made.
I went about a year ago with Skillethead Jr, and while Moms Skillethead was taking a break in the action, we went to Circa on Fremont Street because he wanted to play some poker table games at $5 - $10 instead of $25 at most of the high end places. We sat down first at their mile long bar and had some drinks while the bartender chatted with us and then put on an absolutely dazzling liqour bottle juggling display. We played the games embedded in the bar for about an hour, and he comped us the drinks, which was nice. And then we played some crazy three card poker games and won a bit of money. They also have an absolutely gigantic sports betting arena. I would really recommend going there, and I'm usually in Vegas for the flash.