I went Shannon - Atlanta - Vegas with Delta.
When it comes to hotels, I have the ultimate advice:
Avoid staying a Saturday night if possibe becaus eif there is a convention on, then rates shoot up.
Book 4 or 5 hotels (yes, I'm serious). Use offical hotel website in each case. Observe the rates fluctuate and when they drop, rebook. Just before you leave, decide which one you are going to stay in and cancel all of the others.
On arrival, wrap a $20 bill (or $50!!!) around your credit card and ask for a really good room. This is how you get an upgrade to a suite in Vegas. I was told to do it and I did it and it worked. I saw another guy do it too. If you are checking in on a Fri or Sat, this is less likely to work.
What is the purpose of your visit?
Romance - stay at Venetian
Pools - stay at Mandaly Bay (I did. it's brilliant)
Budget - stay off Strip but remember taxis are dear and it gets hot during the day.
Novelty - stay at MGM, biggest hotel in world
Cheap bed in middle of it all - Imperial Palace or Circus Circus
Let us know how you get on.