"Current" sounding comments are in reference to our visit in November, 2004.
This is by no means a complete or correct list. It's what I know or have experienced in Las Vegas.
There's myth and there's reality. You can find the glamorous side of Vegas still, but you have to dress and pay to make into the those places.
As for activities. If you are into shows, you can do 2 shows a night, but getting tickets is difficult and expensive. However, we have never been disappointed by a LV show.
If you are into architecture, Vegas is wonderful. Look at how the buildings are shaped, decorated and how the interiors are laid out.
Outdoor free shows from fountains to volcanoes to wet Pirates and Sirens.
Try to collect an entire set of the escort baseball cards.
(Window) shop till you drop at Caesar's or Aladdin's giant malls.
Laze by the pool of you hotel and do nothing.
Alcohol your thing? You can't go 50 feet in most casinos without seeing a bar of some sort, or just play some low stake slots or tables get freebies.
Gambling your thing? Lowball Penny and Nickel slots have reappeared. Play for cheap. Take "big" risks and win the jackpot (chriso won 10,000 coins...on a penny slot... But $100 is $100. ;)
Play a $5-10 table of Blackjack (though $2/3 tables seem have disappeared). Some casinos have "theme" tables, to make losing more fun.
Hint for the Imperial Palace Legends Tables-- Don't play with Elwood, Roy or Marilyn as your dealer, do play with Bette or Janet as your dealer)
Animals? Siegfried and Roy's Secret Garden. Shark reef at Belagio.
Rio has Carnival in the Sky twice a day.
Hard Rock and Rio hotels have sand beaches.
Caesar's has a "Euro" pool (topless bathing allowed.)
Naturist/Nudist? There are a couple of Clothing Optional B&Bs that allow day visits and 2 non-landed clubs that seem to do events almost every weekend.
Into SF or Tech? The Star Trek Experience is supposed to reopen this month. Downtown's Fremont experience was being upgraded in Nov, so it's now even more spectacular.
Want a little more heat in your entertainment? Virtually every casino has a dance review ranging from the upscale to the raunchy. Male and Female dancers, wearing very little to nothing at all.
Want it raw? Lots of strip joints, from upscale to you don't even want to walk in the door. The Olympic Club features Guys dancing for Ladies upstairs (and many of them appear to be really interested in Ladies (or are good actors)).
My basic advice: Treat the entire town as one large entertainment zone. Unless you want to go cheap, you will spend $75-150 a day for food and entertainment no matter what you choose to do.