print design - Physical paper weight reference

So here's the thing. When I send an order to a printing shop, I never know what kind of paper I really need. So I just ask them what paper they'd propose me after I explain them the futur use of the print. (ie: flyers, congress name badges, etc.)

Since I didn't have any references, I ordered a couple of free samples from some printing company, such as Moo, Jukeboxprint, PFL and VistaPrint. Of course, it gave me an idea about their product and some paper weights, but I don't find it professionnal enough, neither complete enough.

Also, their standard seems to be quite different. For paper weight, some use "Pt", other use "#" (as in 120#). Sometimes it's "Lb", other times it's "gsm". It's really confusing. I know, there is conversion charts (ex: http://www.akeygroup.com/media/images/Paper-Equivalent-Weight.gif), but it would be nice to have a universal physical reference. Pretty much like any color reference bar :

So, does anyone know where I can find that? If such thing exists.

Thanks