I think everyone's list is different. I did not order loads of extra bobbins. I started out with about 10 as well and then quickly discovered I LOVE prewound bobbins, especially magnaglide prewounds. So you never know.
I still pin my tops and backs to the leaders. I have not yet invested in any other system. Pinning is least expensive and I would rather take a little longer to pin and spend my $$ on other things like fabric, thread, batting, and gadgets.
I love ruler and template work but agree with Alikat that you may not like it so if you only get one ruler to start get a small straight ruler. I am assuming your machine comes with a ruler base, if not you will need one of those if you plan on doing any ruler work. It is impossible to do it without one not to mention dangerous. I pick up my 2" x 6" straight more than any other gadget I own. It is absolutely necessary for SID or any straight line quilting. After that I used my curved arc ruler for curved crosshatch and circles the most. I actually use my circle templates more for marking then actual quilting. speaking of marking, you might want to pick up a couple of blue water soluble markers.
I would also invest in a white board or large pads of newsprint, the 18" x 24" size to practice on. The more you draw a design the better you will be at quilting it. Like signing your name, you can probably do it blindfolded.