I recommend the Wynn. It's on the north end of the strip, but nothing is really that far. Wynn is clean, comfortable and well laid out. Nice sports bet/bar, great restaurants, an adult swim area, etc. Next to shopping plaza, which is cool.
I find the other casinos either too dated, dark, touristy, uncomfortable and/or the gimmicks wear-off quick (though no denying that some of the gimmicks are cool - Paris, NY, Bellagio).