Las Vegas Trips

You must consult this site: http://cheapovegas.com
The best deals I see are on http://swavacations.com (or go to http://southwest.com and click on vacation packages in the quick links section).
Most of the hotels (on the strip) will offer the "casino rate" if you ask. I've stayed at the Mirage many times (also Bellagio/Treasure Island/Paris/Venetian) in suites at the casino rate. I've never used a package deal w/flight - always book directly with the airlines.
I've used Yahoo! Travel before for hotel+flight deals to Las Vegas, and it worked out great! I got Flight + 2 night wknd stay in Luxor (deluxe room) for $250/person including tax and stuff.