What kind of glue do you guys use for your basing materials?  I have grass flocking, Scale rocks, etc but I'm wondering which glue type is best for each.

Depending how you base you can use clear elmers glue or wood glue. If doing gravel as I typically play a city board I use the wood glue, then go over that with some woodland scenic - scenic cement, its just a watered down elmers glue but it dries flat and holds the gravel in place nicely.

 thanks, never would have thought of elmers…

 Also elmers glue is sometimes reffered to as pva glue.

 I use undiluted PVA/Elmer's glue to fix ballast, sand and other bits to the base. You can dilute it a bit but if you work quick and are sparing, there's no need. Then I dilute 50/50 with water and use an eyedropper to fix it all once dry.

PVA works fine for me.

Sometimes even in a mix with water, black color and sand to create some kind of a paste,

which is fine to hold some small terrain bits like skulls, weapons to appear half buried in the ground…

 I'll chime in and add my voice to elmer's!! 

I picked up a 2L jub several years ago, and I'm STILL using it! And that AFTER I based a 8 foot urban ruins table, and probably close to 200 miniatures. 

I have used cyanoacrylite, but that stuff can be dangerous if you're not in a well ventilated area… AND, if you're drilling/carving into it, it can ignite and make caustic gas. 

Found that out the hard way. :S

 Whichever PVA based glue you can get the cheapest