Here is a 3rd vote for Allegiant Air. These days even the full service airlines don't give you much, so you might as well go for the discount airline since you're going to get the same service anyway. http://www.allegiantair.com
I have given up on booking tickets through Expedia or Travelocity-I always get to the hotel and find out I would have gotten a better deal if I just done the hotel resevations directly online or in person on the phone (the other two charge a service charge on top of your already bad deal). Plus, they are inflexible if you want to change rooms or change the dates of travel....
As far as rooms, it is a good idea to ask your friends who have been to Vegas in the last 2 or 3 years before you commit to a room. The MGM Grand looks great on the outside but the basic rooms (at more than $150 night)are tiny and dark. The Luxor also looks great on the outside but the (also overpriced) rooms are not that great for the money-they have a wierd slant since it is a pyramid. Same with the Excaliber (small dingy rooms at high prices). Of course, if you are a High-Roller or have unlimited funds to get the Penthouse Suites-I take it all back! THOSE rooms are great and only $450+/night!
Three "not as popular" places that we stay at on the strip (for a good deal because they aren't as "New" or well-known- and always seem to have great deals) are:
the Tropicana http://www.tropicanalv.com/
which has nice rooms at a good price (under $100/night) and is right in the heart of things,
The Polo Towers, http://www.polotowers.com/
I think they are time shares so you can rent a whole suite from the owners-or we did-around $150 a night but for for 2 bedrooms, a Living Room and a kitchen-good for a group.
I have to add that I haven't been there since they re-did it and it became "Planet Hollywood"-the rooms used to be nice for what you paid.
The downtown area (off the strip) has great deals too. Once we paid $35/night at Fitzgeralds which was fine since we only slept there, but as a whole I have found the rooms to be kind of smaller and dingier in the older downtown from years of use.
Then again, it's Vegas, so who ever hangs out in their room anyway!? Have fun!