Personally I started with one, had him a year or was it two...and then got two more at the same time so right now I have three. Of course when I got the two together only one was a pup and the other was 2 years old so I definitely didn't get two pups at the same time. It seems to have been done though-quite a few recent threads in the general forum about two at once lately, might want to go review them.
I wouldn't recommend getting two initially unless you have lots and lots of at home time or could take them with you etc, maybe that's just me.
Two adult dogs that were needing to be re-homed together might be a really good idea-what a wonderful oppertunity that would be. If you are not all into the puppy idea-there are so many rescues out there that have a pair they don't want to separate and it is so hard to find people willing to take two...just putting that out there. Here's two of the getting two forums from the general category...
http://www.yorkietalk.com/forums/gen...ouble-fun.html http://www.yorkietalk.com/forums/gen...-together.html