Take a walk on the seedier side of Vegas
If you're a hard core gambler and want to take advantage of Vegas' most liberal blackjack rules, great odds on craps, etc., then grab a cab, head to downtown (i.e., Fremont Street) and pop into the Vegas Club. When I started coming to Vegas, I would make it a point to head downtown to do some gambling at least once on every trip. After all, the Vegas Club had the following rules on blackjack: unlimited splitting of aces, 6 card Charlie's (if you get 6 cards without busting, you automatically win, etc.), doubling down on your third card (my personal favorite) and others. These rules used to apply on every table in the casino, but in the past several years, they've limited them to a few special tables. Nonetheless, the Vegas Club will always hold a special place in my heart.
Be warned, downtown Vegas is not the strip. It's much seedier & dodgier than the strip, yet this area is THE original Vegas. It's where you'll find the famous Cowboy and Cowgirl with swinging leg electric light signs, Binion's horseshoe (the original location of the World Series of Poker), and other familiar sights.
Yet with all the seediness of downtown, there's a certain amount of charm mixed in with the degenerate gamblers and alcoholics and I still love to head down there to people watch, play some hands at the Vegas Club and enjoy some late-night comped Chili's at the Vegas Club's diner.
Unique Quality: Very cheap rooms (that aren't too bad for the price, actually). Great gambling rules & odds.