don't stay at Circus Circus. It's full of kids. Yuck. It's also a taxi-cab ride to anything worth seeing on the strip. Circus Circus is the worst place to stay for 3 guys.
Stratosphere is gross, it's next to the Projects (not kidding). So... you'll find a lot of project-people gambling there. It's a step above Circus because it has no kids. I can't be really honest and tell you what the Strat is really like... because the SBR police will be on me... but, I'm sure there's reviews that will tell you (clue: it rhymes with Tigger) and those reviews are all true.
I'd recommend Imperial Palace, Harrah's, Flamingo, Bally's or for the ultra-cheap, Orleans. Imperial and Harrah's is a dump but it's smack in the middle of the action. Flamingo and Bally's is ok, but tad pricier, and it's next to Cesar, Bellagio and Planet Hollywood.
Orleans is dirt cheap, but it's off the strip, but they have a very popular shuttle that leaves every hour to go to the strip and it's free. You'll also find a boatload of degens there and there's pubs and strip clubs galore around the hotel.
Hope that helps.