Taxi who? The monorail is awesome...specially when it's located inside the hotel you're staying in! Stayed at the LVH and the monorail was an inexpensive way to get to the strip. Single rides are $5, $12 for all day, or $28 for a 3 day pass...totally worth the price. Comes every 5 minutes and never full :) Cabs can get expensive so if you want to travel throughout the strip, I would suggest the monorail!
The only con is that it rides on the east side of the strip and leaves you on the back side of the hotels (unless it stops inside the hotel; ie. LVH, MGM). So, there might be a bit of a walk depending on where you're trying to go. Still not a bad deal though.