Mapquest says a tad over 5 hours, but we’ve never made it in less than 6-7, given winding roads with lots of RV traffic. Less in winter, but still…
I will admit my earlier suggestions were made with the idea of ‘first-time’, rather than ‘once-in-a-lifetime’ type travel. If this is the only visit Jophiel and his ladylove expect to make to the area, Hoover Dam and the GC are head and shoulders above ANYTHING in Las Vegas.
I apologize for my ‘been there, done that’ attitude.
'Cuda
On the off chance that you want to get away from the glitz and crowds, and take a nice drive in the desert,Valley of Fire is about an hour away. There is some really spectacular scenery along the way on North Shore Road as well. Red Rock Canyon has already been mentioned, it’s a beautiful spot.
There are people who see the desert as a wasteland, and those who think it’s a place of wonder and awe. You could say the same about Las Vegas.
Thanks all for the tips and feel free to share more. I’m soakin’ them in.
If the ladyfriend is interested, Hoover Dam might be worth the 30min drive out. While I’d love to see the Grand Canyon, an eight-twelve hour drive seems a bit excessive given our short time in town. Plus, I wouldn’t want to risk getting hung up on the return drive and missing the only business obligation being imposed upon me for the trip.
There is a very nice evening City Tour available which is worth taking, IMHO. It costs around $25-$35 and lasts about 3-4 hours. They take you to the top of the Stratosphere; downtown for the light show; The Rio for the floor show; The Tropicana for the floor show; the Fountains at The Bellagio and various other places. Be prepared to walk and stand a bit - I took my 78 year old mom on the tour and she had a blast, so it’s not too taxing. All in all, it’s a nice overview of Vegas and you get a bit of Vegas history from the tour guides. (Take a jacket as it can get rather cool at night)
Mandalay Bay has a great all you can eat breakfast buffet FYI.
When I went to Vegas in 2004 I was there for a week for a convention, but I still made time to hang out.
My favorite things (as a firt-timer, non-gambler):
Mandalay Bay aquarium
the Star Trek thingies at MGM (?)
topless burlesque show at the Tropicana (really good - and i’m a woman!)
a gondola ride at the Venice hotel
walking around and “experiencing” all the hotels on the strip
Avoid the Treasure Island “Sirens” thingie - yeah, it’s free, but it sucks. It’s not the pirate ship battle it used to be (although there still are the ships, and one still sinks). Now it’s all bad singing and bad whip cracking and it’s just not good. Don’t waste your time. Spend that time at the Bellagio fountains instead.
Call room service and request a case of grapefruit and a Gerber Mini-Magnum. 
And turn “White Rabbit” up as loud as it will go.
We went to the Valley of Fire on our trip. It was pretty awesome. Well worth the trip.
I meant to add that I liked this better than the Hoover Dam.