In addition to the casino rounds, food, Grand Canyon day trip and other entertainment, don’t miss out on the Cirque Du Soleil shows in Vegas. Expensive, but if you are making a ‘once-in-a-lifetime’ trip, you can’t afford to miss these. I would recommend O at the Bellagio and/or Ka at MGM

Sounds like you just want a list of more 21+ (not child type of guides) travel guides. I’m 27 and I understand what you’re getting into. I’ve been to Vegas a lot for conventions (photography more specifically). Last time i was there was ’09. Vegas grows so fast. There are already new hotels sprouting when I was there, like Aria (newest hotel / condo / loft / megaplex).

21+ Travel Guides

There are also excellent guides from the travel channel on 21+ :

• Travel Channel’s 21 sinful vegas hotspots

• Travel Channel’s guide to Vegas Extreme Pool Scene – Great guide. Has list of crazy pool parties. Not sure if you’ll get that in October.

• Bert the conquerer has some great things that he did here as well. I would check out the rides at the Stratosphere (x-scream ride). They’re really extreme. Video here

If you get bored and those don’t excite you, you may still want to do touristy things; so when people ask you can’t just say you can’t remember it:

Lodging

The best places to stay are around the middle of the strip. If you’re in the middle then you’re not too far from everything. If you’re stuck on the north or south end you may do a lot of walking. That really sucks. Hotels include:

• Planet Hollywood – Perfect spot and value. It used to be known as the Aladdin. The rooms have been remodeled and redone to fit the planet hollywood theme. They always have deals on hotel rooms. Probably the cheapest; I may be wrong.
• Bally’s / Paris Las Vegas – These two hotels are right next door to Planet Hollywood. They’re connected and owned by the same group. Rates are a bit more but this is the best spot of the new strip. Bally’s is the older of the hotels but their rates are a bit inflated.
• New York New York – This hotel is a little farther south. Not too much extra walking and closer to the south end of things. Prices may be similar to bally’s.

Walking Attractions

The best part of Las Vegas is the walking attractions. Walking around hotel to hotel can be very fun and a good way to walk off a hangover.

Here are some hotels you must visit:

• NY, NY – Just walking through this hotel is great. They have lots of great sites that remind you of New York. It’s the only roller coaster hotel on the strip.

• Paris Las Vegas – worth a visit. They have a crepe shop and a restaurant on the top of the scale model Eiffel Tower where you can have brunch. Not sure if it’s appropriate for bro-mance times. It’s more of a romantic thing apparently. If you’re lucky you may also catch the mime that appears near the convention center (toward the far back).

• Palms – It’s off the strip so I never went. But this is the home away from home of the Playboy Mansion. There’s lots of great things here I hear.

• Bellagio – Walk through the lobby. There’s a fun garden and chihuly glass in the lobby. There’s some fun attractions. The pool at the Bellagio is the most ridiculous sight. It’s worth checking out. If you walk toward the back you’ll be able to see the nice views. Make sure to watch the movie Oceans 11. You can catch the fun spots where they filmed it. You can also find the best blackjack tables. There’s $5 minimum blackjack table that gets a lot of visits and i’ve won a lot of decent hands there.

Food

I have only been to the buffets. It’s hard to find food around the strip that isn’t a buffet. So here’s a couple you should visit. If it’s sit down in Vegas it’s going to be really hard to find a decent meal for under $10 per person. If you do the food quality is very poor. They take advantage of the tourists.

• Planet Hollywood’s buffet – Go on a Sunday. They serve brunch and it’s of the best besides the Bellagio
• Bellagio buffet – Go right at the cutoff between brunch and lunch and you’ll get a great deal. The price for the Bellagio buffet is steep. But by far the best buffet hands down. They have everything.

Bars/Clubs that you must visit

If you want more loungey bars New York New York may be the better place to be.

• Coyote Ugly – Apparently a hot spot at New York New York
• Tao – one of the most extravagent night clubs. The line at midnight is ridiculous. You may want to get there really damn early.
• XS – Home of the most expensive drink

Shopping

• Forum Shops at Caesar’s Palace – Caesar’s Palace offers lots of fun shops. There are several drink stands in Caesar’s Palace that offer you 151 in a 711 type slurpie cup. It’s a great value.

• Wynn – The Wynn has some high end shopping stores. Nothing super exciting though. Everything is way too expensive.

• Venetian – The Venetian has an entire mall. It’s several floors. Some of it is interesting.

• Las Vegas Premium outlets – Take a cab there. May cost quite a bit. But worth the adventure. You’ll save on lots of great things. Everything on the strip is too expensive.

• Shops at the Stratosphere – There’s a mall here you can walk through.

I am bit confused because you say “visiting las vegas” and “we don’t want it to be to much of a tourist thing”. Las Vegas is a tourist thing.

If you want to get drunk then visit the Hooters opposite the MGM. You find a lot of people handling out flyers for strip clubs on the main street (The Strip), and there is a place where you rent a ferrari or lambo for an hour or so, and recently some company opened where you can drive a bulldozer or digger and shovel some dirt around. “Sahara” had some ex Daytona racing cars set up as multiplayer racing game simulator, but the place closed down sometime in May 2011 – I blame the food.

Apart from that you can only really hang out in Casinos and watch the shows there, or the one shaped like a pyramid has the worlds largest Titanic collection inside.
The casinos itself might all have a different theme, but at the end it’s just plastic decoration around gambling machines and they are all the same.

I really recommend some day trips to either the Grand Canyon, Hoover Dam or maybe Bodie, CA on the way from LA to LV.