Are the "cute little plastic cases" of needles Schmetz brand by chance?
I prefer this brand in many different sizes and uses over all others. In general I machine piece my quilts with Schmetz Universal 80/12 or 75/11. There is also a Schmetz "Quilting" needle which I use for machine quilting the layers together.
This book, newly back in print, is the definitive article on needles.
http://pointwelltakenbook.com/
Jan in VA