I get my stabilizers from All Stitch. Here is their stabilizer page. At the bottom, there are several links to articles that talk about different stabilizers and how to choose & use them:
http://www.allstitch.net/department/....cfm?killnav=1
Since there are about 7,986 different brands and stabilizer types out there, it can be overwhelming. Read the articles and get small amounts of different stabilizers from different manufacturers and eventually you will come up with favorites. As you collect them make sure that you label them! They will all start to look alike and you won't be able to find the one you need.
As far as embroideries for quilt blocks, it's a balancing act. You have to use a stabilizer that will support the density of the designs you are using, so without knowing what designs you're using it's hard to suggest a stabilizer. the down size is that it may make the blocks stiffer than the rest of the quilt. When I took my first class with my embroidery machine, the instructor told us that the most successful embroideries were ones where the designs matched the weight of the fabric. Best advice ever. Basically, lightweight fabrics, use less dense (sheer, redwork etc.) designs and save those bullet-proof ones for canvas tote bags!