I was referred to this board several years ago by someone here:
vegasmessageboard.com
And as well I have referred tons of people back here LOL! The one compliment I can give that board is you virtually never get 'snarked' at- which you often will on some of the others (not picking on any in particular).
IP is pretty plain but one of the cheapest you will be able to get that is still in the heart of the strip. Trop is near the south end, but you can still access everything with taxi, deuce/SDX bus, etc. Flamingos basic rooms will be a good rate, right at center strip but will be pretty basic - equate to a mid-level Super 8 or along those lines. However, I have read several reviews lately that said the rooms were clean & beds were comfy. Ballys is also a good choice. Not sure on trop, but the other 3 are Ceasar's props & have no resort fees.
I would avoid the Riv because it is a bit more isolated & I haven't really read good reviews on it lately. Circus Circus freaks me out with that big clown sign. I had a girlfriend stay there & they thought it was fine, but others can't stand it.
Which brings us to the matter of when selecting a hotel, make sure you are calculating any resort fees into the final price so you know what you are paying for.
Cirque is having a Summer of Cirque special again - you can get 2 tickets for $100 (plus ticketmaster fee) to many of their shows. You can view schedules & pre-purchase online. Try to read reviews of some of the shows - personal taste can be the deal-breaker. I love LOVE (Beatles Cirque show), Mystere is good, etc. Chris Angel gets AWFUL reviews. Terry Fator has a great show (at Mirage). Human Nature is an awesome show (at IP).
Other freebies - the volcano show at Mirage - the gardens to stroll thru behind Flamingo (& memorial to Bugsy Segal), the chocolate fountain behind the Bellagio Conservatory (as well as of course the conservatory!).