I agree with any of the neutral threads, maybe a cream or beige if you are making the quilt in an ecru or beige.
I have been using Connecting Threads for years and love it, low fuzz, 100% cotton Egyptian long staple...really inexpensive compared to other big name threads. Recently bought a couple of their 5000yd cones that only cost $7.99 ...oh my gosh how can you beat that? Use the coupon code FPSHIP to get free shipping.
For the bobbin I highly recommend Superior Threads Bottom Line ... You can get it at a great price at Sewthankful.com it is cheaper there than from Superior threads. I have found that any of the lighter colored Bottom Line will work with light quilt backs and a darker thread will work for any dark fabrics.
Also, if you have any questions on threads, what kind to use cotton vs poly etc. Superior Threads has a great educational page.
Have a great time in your class and please post pix when you get your quilt going, we love photos.
warm quilt hugs, sue