My first vote is still for PaxEast for obvious baby related reasons for me, but since I was the one who put Vegas on the list...
First of all, I've planned 2 group trips to Vegas before so I know how to do this. Both were in February (the most recent being Feb 09) so I've got some experience.
Right off the bat- Embassy Suites is a big fat NO. It looks close to everything but it's not- unless you have a really good reason, you really want to stay on the strip- it just makes it that much more fun and accessible to everything.
Sure, happy hour... dude, it's vegas! Go play penny slots and it's happy hour EVERYWHERE 24-7! You can put $5 into a machine and get loaded on the free drinks.
But no worries, I know the perfect place for a group:
The Jockey Club: Shit Anywhere.
Seriously, this place is a hidden gem. It's RIGHT next to the belliago, as in rooms on 1 side can watch the fountains. It's in the perfect ideal spot on the strip. It's not a casino, so it's quiet if you want that and you don't have to drag luggage through slot machines. It's cheap ($100ish a night), but best of all is that the rooms are friggin' enormous. The living room (with pull out couch) is 500 sq ft at least alone. The bedroom is the same size. There are 2 bathrooms and a full kitchen. We had 5 in the suite and couldn't even feel it. If people wanted to snuggle, the beds were awesome. If anyone wanted to floor it, 12 people could fit in a room, seriously. http://www.jockeyclubvegas.com/
I personally like getting a couple of big rooms rather than a bunch of small ones- it makes it all so much more fun.
But, if we wanted to be in a traditional hotel with a pool, etc that's totally doable too and I've done research on that side as well.
I'm all about getting good deals. Vegas has a lot of free stuff available and can be done cheaply, though it's a lot more fun with money. The strip clubs aren't cheap, shows are really pricey, and there are some great day trips, but pricey as well.
My first vote remains for something a little lower key to not take away from the hanging out, but I will hardly ever pass up an opportunity to go to vegas if there is a reason.