Las Vegas is the perfect spot to have a reunion for a variety of reasons:
*Lots of airlines fly into McCarran airport making it convenient for people from all over the U.S. and Europe to fly into.  
*It is "family friendly" thus making it easy to plan your family vacation around.  
*It's an interesting city with a million things to do (check out the "things to do" link below and you'll be amazed - each hotel on the strip has it's own attraction to lure you into their casinos).
*Getting around Vegas is simple!!!  Rental cars aren't necessary unless you plan on visiting sites off the strip.  Las Vegas is the place where free drinks come with your gaming experience so it is always a good idea to opt for the taxicab (they're everywhere). Traffic is busy so let others do the driving for you.  The Las Vegas Strip Trolley (for$1.50) makes its way along Las Vegas Boulevard from 9:30 – 2am every day.  You can also catch a ride on the monorail system. As you can see, transportation is a "non-issue" in Vegas (see the "air & car" link below, the airport link is useful as it gives both air and ground information, monorail link too).